The objective of this work is to develop regenerable sorbents that have high selectivity, efficient regenerability, and high adsorption capacity for CO2 over wide temperature ranges. These properties are critical for the success of the PSA/PSS and TSA/TSS processes.
... TITLE (Include Security Classification) Sorption of Selected Volatile Organic Constituents of Jet Fuels and Solvents on Natural Sorbents from Gas ...
This study was aimed to test and select hydrophobic activated charcoal, manufactured in Romania, used as adsorbents of solvents which partly compose diluters employed in car industry. With regard to the diluters, three of the seven types of activated charcoal studied (Sorbent 1, R - Cafs and AD3) showed the greatest capacity of adsorption, when determined under dynamic and static conditions. (authors) 8 refs.
The nanosized luminescent Tb-MCM-41 (1:10) is synthesized by means of sol-gel-assisted self-assembly under basic conditions at room temperature. The results of "2"9Si-MAS NMR and XRD prove that Tb"3"+ doped Si-O framework. The HRTEM image shows that the regular uniform particles with a diameter of 10 nm possess ultralarge pore with diameter 2.0 nm, which is consistent with the result of N_2 adsorption. The BET surface area and porosity of Tb-MCM-41 (1:10) are 1127 m"2/g and 0.84 cm"3/g, respectively. The patterns of selected-area electron diffraction and XRD of Tb-MCM-41 (1:10) show an Fm3m space group in the cubic. FT-IR results show that the peaks near 970 cm"-"1 are assigned to the deformation vibration of silanol group. The as-products are calcined at 800 deg. C and the mesoporous materials possess enormous specific areas and large porosity, it shows that the mesoporous materials are ultrastable.
Bench-scale batch equilibration tests have been conducted with supernatants from two underground tanks at the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to determine the effectiveness of selected ion exchangers in removing cesium, strontium, and technetium. Seven sorbents were evaluated for cesium removal, nine for strontium removal, and four for technetium removal. The results indicate that granular potassium cobalt hexacyanoferrate was the most effective of the exchangers evaluated for removing cesium from the supernatants. The powdered forms of sodium titanate (NaTiO) and cystalline silicotitanate (CST) were superior in removing the strontium; however, for the sorbents of suitable particle size for column use, titanium monohydrogen phosphate (TiHP {phi}), sodium titanate/polyacrylonitrile (NaTiO-PAN), and titanium monohydrogen phosphate/polyacrylonitrile (TiP-PAN) gave the best ...
The present study was carried out to exploit the feasibility of using polymeric nanosponges as an alternative carrier for targeting econazole nitrate (EN) to the skin through topical hydrogel formulation. Nanosponges prepared by emulsion solvent diffusion method were evaluated for various physicochemical parameters and in vitro drug release. The nanosponges of EN were discrete free flowing nanosized particles with perforated orange peel like morphology as visualized by SEM. The nanosponge formulated using PVA:EC (3:2) displayed highest in vitro release after 12 ?h in phosphate buffer (pH 6.8) that fitted matrix model. Selected nanosponge was formulated as Carbopol 934 NF hydrogel using varying concentrations of permeation enhancers propylene glycol and N-methyl-2-pyrrolidone. The EN nanosp...
This paper aimed to the evaluation of different kinds of sorbent material preparation and to the evaluation of their characteristics at different pH conditions by X-ray fluorescence analysis. This method is suitable for identification and determination of elements in samples of different character, state and origin because it is a polycomponent, non-destructive, fast and simple analytical method. Moreover, it allows timeadvantageous and reliable measurements. This paper studies problems concerning the determination of some selected elements (Mn, Fe, Ni, Cu, Zn, Pb) in pharmaceutical samples of sodium chloride in the solid state as well as in its solution by sorption on chelating extraction membrane 3M Empore"T"M and on the strongly acidic ion-exchanger Dowex 50Wx8. Conditions for the most effective sorption of determined elements are also interpreted. (author)
This paper aimed to the evaluation of different kinds of sorbent material preparation and to the evaluation of their characteristics at different pH conditions by X-ray fluorescence analysis. This method is suitable for identification and determination of elements in samples of different character, state and origin because it is a polycomponent, non-destructive, fast and simple analytical method. Moreover, it allows time-advantageous and reliable measurements. This paper studies problems concerning the determination of some selected elements (Mn, Fe, Ni, Cu, Zn, Pb) in pharmaceutical samples of sodium chloride in the solid state as well as in its solution by sorption on chelating extraction membrane 3M Empore? and on the strongly acidic ion-exchanger Dowex 50Wx8. Conditions for the most ef...
This report contains detailed information of the research program entitled "Development of Bulk Nanocrystalline Cemented Tungsten Carbide Materials for Industrial Applications". The report include the processes that were developed for producing nanosized WC/Co composite powders, and an ultrahigh pressure rapid hot consolidation process for sintering of nanosized powders. The mechanical properties of consolidated materials using the nanosized powders are also reported.
A fusion reactor (such as NET/ITER) which breeds its own tritium fuel requires tritium recovery, purification and separation from the other isotopes. Cyclic adsorption processes are strong candidates for several of the processes involved: amongst other advantages, they promise a low tritium inventory. A good adsorbent for such processes must have high adsorption capacity, high selectivity and very low tritium retention after each cycle. Pure zeolite powder is shown to have an excellent combination of these three properties. However, in practice problems can arise from tritium which is not removed by reactivation. In this paper we show that tritium retention in zeolites can be caused either by water retained in the zeolite structure, which can be removed by ore rigorous activation, or by water tapped on binders in commercial pellets. (orig.).
Feasibility of using fixed bed column of conventional ion exchangers/sorbent and chemical precipitation based processes have been examined for the effective removal of the very low levels of 106Ru activity from NH4NO3 effluent generated during wet processing of rejected sintered depleted uranium fuel pellets. Based on the results, a simple process involving precipitation of cobalt sulphide along with ferric hydroxide was selected and further optimization of process variables was carried out. The optimized process has been found to be highly efficient in reducing 106Ru activity down to extremely low levels.
Combustion characteristics of Korean anthracite in a circulating fluidized bed and freeboard were investigated. A test coal was selected with heating value of 4,429kcal/kg and ash content of 38%. Characteristics of combustion, sorbent effect on desulphurisation and emission of SO{sub x} and NO{sub x} were monitored by varying process variables such as feed rate, (Ca+K)/S ratio, and excess air ratio at the given properties of coal. Optimum operating conditions were studied by analysing: axial profiles of temperature, effect of excess air ratio, characteristics of loopseal and bag filter ashes, and emission of toxic gases. 9 refs., 9 figs., 3 tabs.
Shaped activated charcoal is modified by 02 and N2 processing for producing coal compounds with higher acidic or basic properties. Nitrated activated charcoal has properties of a weak anionite with a substantially increased ion exchange capacity with an increase in the concentration of the hydrogen ions in the electrolyte and adsorbs iodine ions well from aqueous solutions at a pH of less than 5. A layer of nitrated charcoal is a very effective sorbent in the process of dynamic sorption of iodine anions from acetic solutions of KI. It is also established that the sorption of iodine ions in the activated charcoal modified by 02 occurs in accordance with an ion exchange mechanism (and possibly, selective sorption). This refutes literature data which ascribe the determining participation in the process to the reaction of oxidation of iodides on the surface (Pv) of the coal into free I2.
Natural minerals and some industrial wastes are used as low cost sorbents for removal of metal ions from effluent streams. Apatite as natural mineral and red mud as an industrial waste have been tested for their sorption properties with respect to two important fission products "1"3"7Cs and "9"0Sr. Their ion exchanging capacity was tested after every 4 hours till 24 hours. The material gets saturated after 4-8 hours. Hence these materials can be considered for treating in treating LLW before discharge, industrial waste treatment and as backfill or admixture material for shallow land repository. (author)
In contrast to plants based on formed coal where, for the purposes of calculating sorbent volume, only one activated charcoal design can be used in a filter layer, powder sorbent technology enables two variations to be used. This can be either a mixture of a number of different activated charcoal forms in one and the same filter layer, or the combination of a number of filter layers on top of each other, each containing a different activated charcoal form, in one and the same construction unit.
A multiple metal oxide sorbent supported on a zeolite of substantially silicon oxide is used for the desulfurization of process gas streams, such as from a coal gasifier, at temperatures in the range of about 1200.degree. to about 1600.degree. F. The sorbent is provided by a mixture of copper oxide and manganese oxide and preferably such a mixture with molybdenum oxide. The manganese oxide and the molybdenum are believed to function as promoters for the reaction of hydrogen sulfide with copper oxide. Also, the manganese oxide inhibits the volatilization of the molybdenum oxide at the higher temperatures.
The paper discusses recent work on lime enhancement and testing at the bench-scale, followed by evaluation of the more promising sorbents in a pilot plant to develop low cost, retrofittable flue gas cleaning technology specifically the development of highly reactive sorbents. Con...
Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory`s (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling of the melt results in a solid monolithic waste form in which contaminants have been completely surrounded by a polymer matrix. Heating and mixing requirements for successful waste encapsulation can be met using proven technologies available in various types of commercial equipment. Processing techniques for thermoplastic materials, such as low density polyethylene (LDPE), are well established within the plastics industry. The majority of commercial polymer processing is accomplished using extruders, mixers or a combination of these ...
The polyene antibiotic Amphotericin B (AMB) is one of the first therapeutic agents to be marketed commercially as nanosized formulations in which the drug is associated with lipids as liposomes or complexes....Full Text Available
Nano-sized silica is a promising material for disease diagnosis, cosmetics and drugs. For the successful application of nano-sized material in bioscience, evaluation of nano-sized material toxicity is important. We previously found that nano-sized silica particles with a diameter of 70nm showed acute liver failure in mice. Here, we performed histological analysis of major organs such as the liver, spleen, lung, kidney, brain and heart in mice, chronically injected with 70-nm silica particles for 4weeks. Histological analysis revealed hepatic microgranulation and splenic megakaryocyte accumulation in these 70-nm silica particles treated mice, while the kidney, lung, brain and heart remained unaffected. Thus, liver and spleen appear to be the major target organs for toxicity by the chronic a...
A rapidly hydrated sorbent for moderate-temperature dry flue gas desulfurization was prepared by rapidly hydrating adhesive carrier particles and lime. The circulation ash from a circulating fluidized bed boiler and chain boiler ash, both of which have rough surfaces with large specific surface areas and specific pore volumes, can improve the adhesion, abrasion resistance, and desulfurization characteristics of rapidly hydrated sorbent when used as the adhesive carrier particles. The adhesion ability of sorbent made from circulation ash is 67.4% higher than that of the existing rapidly hydrated sorbent made from fly ash, the abrasion ratio is 76.2% lower, and desulfurization ability is 14.1% higher. For sorbent made from chain boiler ash, the adhesion ability is increased by 74.7%, the desulfurization ability is increased by 30.3%, and abrasion ratio is decreased by 52.4%. The ...
Nano-sized particles of a lithium ion conductive solid electrolyte, LiTi{sub 2}(PO{sub 4}){sub 3}, were prepared by laser ablation. The obtained particles were ca. 10nm in diameter. X-ray powder diffraction and Raman spectroscopy showed that they were amorphous with local structure similar to the crystalline counterpart. They were crystallized by the heating at ca. 630{sup o}C. (author)
Nanocrystalline cemented tungsten carbide has attracted considerable interests for use in cutting tool because of its superior mechanical properties. In this study, nano-sized powders of mixed WC and Co were prepared from attrition-milled oxides by a gas reduction-carburization process. The effects of compacting pressure, heating schedule, additional ball-milling, and the presence of a grain growth inhibitor on the sintering properties of the nano-sized WC-Co powders were examined. The grain size and phases in WC-Co alloy were clearly affected by compacting pressure. Because of the trapped gases and the lower melting point of the cobalt binder, when a compact of nano-sized WC-Co powder was sintered through a heating schedule with holding steps, the sintered alloy maintained the small size of WC grains without any {eta} phase. In addition, the additional ball-milling improved the microstructure and mechanical properties of ...
Nanocrystalline cemented tungsten carbide has attracted considerable interests for use in cutting tool because of its superior mechanical properties. In this study, nano-sized powders of mixed WC and Co were prepared from attrition-milled oxides by a gas reduction-carburization process. The effects of compacting pressure, heating schedule, additional ball-milling, and the presence of a grain growth inhibitor on the sintering properties of the nano-sized WC-Co powders were examined. The grain size and phases in WC-Co alloy were clearly affected by compacting pressure. Because of the trapped gases and the lower melting point of the cobalt binder, when a compact of nano-sized WC-Co powder was sintered through a heating schedule with holding steps, the sintered alloy maintained the small size of WC grains without any #eta# phase. In addition, the additional ball-milling improved the microstructure and mechanical properties of ...
Red mud is a kind of alumina production, characterized by high content of fine-dispersion Fe, Al and Ti oxyhydrates; it is studied from the viewpoint of its application as a sorbent for Sr. The red mud specific surface constitutes 23-25 m"2/g, the density is of 3.3-3.4 g/cm"3 and the melting temperature is 1350-1370 deg C. It is established that the maximum sorption capacity of the red mud for strontium equals 420 #+-# 24 mg-eq/100 g. The red mud high sorption properties make it possible to recommend it as a sorbent by constructing technogenic barriers at the radioactive wastes disposal sites
The removal of toxic metals and alkalis from gas streams at high temperatures was investigated. This is important for the development of coal-fired combined cycle power generation systems.
High performance sorbents for flue gas desulfurization can be synthesized by hydration of coal fly ash, calcium sulfate, and calcium oxide. In general, higher desulfurization activity correlates with higher sorbent surface area. Consequently, a major aim in sorbent synthesis is to maximize the sorbent surface area by optimizing the hydration conditions. This work presents an integrated modeling and optimization approach to sorbent synthesis based on statistical experimental design and two artificial intelligence techniques: neural network and genetic algorithm. In the first step of the approach, the main and interactive effects of three hydration variables on sorbent surface area were evaluated using a full factorial design. The hydration variables of interest to this study were hydration time, amount of coal fly ash, and amount of calcium sulfate and the levels ...
We describe the synthesis and characterization of superparamagnetic iron oxide nanoparticle based heavy metal sorbents with various surface chemistries that demonstrate an excellent affinity for the separation of heavy metals in contaminated water systems (i.e. spiked Columbia river water). The magnetic nanoparticle sorbents are prepared from an easy to synthesize iron oxide precursor, followed by a simple, one-step ligand exchange technique to introduce the organic surface functionality of interest chosen to target either specific or broader classes of heavy metals. Functionalized superparamagnetic nanoparticles are excellent sorbent materials for the extraction of heavy metal contaminants from environmental and clinical samples since they are easily removed from the media once bound to the contaminant by simply applying a magnetic field. These engineered magnetic nanoparticle sorbents have an ...
An absorption method of elimination of liquid radioactive wastes (LRW) of low and intermediate activity level by decreasing their contamination up to the level permitting their discharge into the environment is proposed in the paper. The LRW decontamination is accompanied with efficient compacting the resulting secondary solid wastes. The method is based on the use of a new very efficient, chitin containing natural fiber bio-sorbent, Mycoton, which is manufactured commercially in Ukraine. The chemical composition of the sorbent and its highly developed surface provide practically unrestricted opportunities for producing its modifications having any necessary absorption and operational characteristics. The effects of pH, the presence of various salts and complexing agents, as well as of some other factors to the distribution coefficients of the most important radionuclides have been carefully studied in experiments with Mycoton and its ...
A particle-laden turbulent reacting flow model is described and applied to in-furnace, dry SO_2 control in boilers. Sulfur capture by calcium-based sorbents is represented by a shrinking core model which accounts for surface areas loss and product layer diffusion. Sorbent particle trajectories and dispersion are followed with cloud statistics in a Lagrangian framework. The turbulent fluid mechanics and chemical reactions are coupled, and solutions obtained for mean and fluctuating velocity, composition, and particle position. Comparisons are made with data from an US EPA laboratory reactor. Practical implications for SO_2 control are examined including the effects of jet velocity, sorbent injection location, boiler load and thermal profiles.
Spherical nano-sized YSZ (yttria stabilized ZrO2) powders were successfully synthesized via a reverse microemulsion system. The water droplets in the microemulsion system of yclohexane/water/span85/Triton X-100/hexyl alcohol can act as the nano-reactors which solubilize zirconium oxychloride and ammonia water separately. The minute original reactors are favor to the formation of nano-sized spherical YSZ powders and the dispersibility of the powders can be controlled effectually by adjusting the weight ratio of the LiNO3 molten salt to the precursor. The phase transformation from cubic to monoclinic starts at and 500??C and finally monoclinic and cubic phase with increased crytallinity coexist at 800??C. The effect of LiNO3 molten salt in the formation of YSZ powders was also discussed.
Achievements in the field of sorption recovery of uranium from sea water are considered in brief. Polyacryl amidoxime chelate iorites are shown to exceed in sorption properties both titanium dioxide base natural adsorbents and styrene base synthetic resins. Merits of sorbents containing fixed layer of humic acid are pointed out, different methods of their application are considered. The cost of uranium recovery from sea water using different sorbents is estimated.
Radionuclide (R) sorption from a solution (vapor) by freshly formed crystals with production of substitution solid solutions under different types of self-disordering is studied. Changes of self-defectiveness and macrodefectiveness with time and effect of radiation defects in the presence of P macroquantities are taken into account. An analysis for monodispersed sorbents is performed. It is shown that the achievement of equilibrium within a reasonable time in impurity-solid phase system depends on defectiveness which ensures a required level of the coefficient of impurity diffusion in sorbent crystals.
The report gives results of a study of sintering and leaching mechanisms of fly ash/spent sodium sorbent mixtures from a dry injection flue gas desulfurization (FGD) process. It includes an estimate of the economics of pelletizing and sintering to handle the fly ash and spent sor...
Lithium-ion batteries are becoming more and more important not only for portable electronic devices, but also in prevision of high power electric vehicles. In such an optic, deep studies regarding all the components of a secondary battery are in development. In this study, high voltage cathode materials have been selected. Crystals with spinel structure have a 3D vacancy pathway suitable for Li-ions transport. The material under study was LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} doped with magnesium replacing the nickel. Various samples were synthesized via three different routes: a solid-state method, a modified sol-gel method and a xerogel method. The structure and morphology of the powders were analyzed with HRTEM and XRD. Electrochemical tests were also performed. A wide range of particle sizes (from micro to nanosize) was the result of the different synthesis routes. Unfortunately pure materials were not always obtained. The electrochemical tests ...
This paper deals with preparation of PE clay nano composite specimen for transmission electron microscopy (TEM) and studying the difference between dispersion of clay in low density polyethylene using poly(hydrogen methyl siloxane) (PHMS) as coupling agent and untreated one. Argon ion milling is the conventional means by which film sections are thinned to electron transparency for TEM analysis, but this technique exhibits significant problems. In particular, selective thinning and imaging of sub-micrometer inclusions during sample milling are highly problematic. We have achieved successful results using the focused ion beam (FIB) lift-out technique, which utilizes a 30 kV Ga"+ ion beam to extract electron transparent specimens with nanometer scale precision. Using this procedure, we have prepared a number of thin film materials representing a range of structures and compositions for TEM analysis. We believe that FIB milling will create major new opportunities in ...
The gas-solid reaction and breakthrough curves in the fixed-bed reactor are of great importance, and being influenced by a number of factors makes the prediction of these factors a difficult problem. In this study, the reaction rate between solid sorbents and hydrogen chloride gas at high temperature was first investigated. On the basis of a fixed-bed reactor, the experimental results were analyzed by the shrinking core model of diffusion and surface chemical reaction control. The results showed that reaction rates of two sorbents with hydrogen chloride gas were controlled by the combination of the surface chemical reaction and diffusion of product layers, and the reaction rates nearly keep constant within 15 h of the initial reaction period and then decrease gradually. The results of the breakthrough curves show that solid sorbents in the fixed-bed reactor are capable of reducing the HCl level to near-zero levels at ...
Under typical conditions found in Pressurized Fluidized Bed Combustion (PFBC), the calcination reaction of limestones is thermodynamically inhibited, and the sorbent reacts with SO{sub 2} by a direct mechanism. Direct sulfation reactivity of different Spanish sorbents was studied by high-pressure thermogravimetric analysis. It was found that the physical structure of the surface of the particles influence the sulfation behaviour of the sorbents. Total pore volume and pore surface area correlated well with the reactivity of the sorbents. Temperatures between 800 and 925{degree}C, and pressure between 12 and 25 bar, promoted an increase in reactivity, while the gas composition had no effect when changed from 15% CO{sub 2}, 3% O{sub 2}, 0.5% SO{sub 2}, balance N{sub 2} to 12% CO{sub 2}, 7% O{sub 2}, 0.5% SO{sub 2}, balance N{sub 2}. It was found that the unreacted shrinking core model could not ...
The aim of this study was to search for a sorbent that could act as an extraction phase and as a support for solid-matrix time-resolved luminescence (SMTRL). Four potential sorbents were investigated for this purpose using tetracycline (TC) as a model analyte. Sorbents prepared from C18 silica gel or calcium cross-linked pectin gel were able to extract TC from dilute solutions. Europium(III)-TC complex adsorbed on the surface of C18 generated the most intense TRL signal when measured at {lambda}{sub ex} = 388 nm and {lambda}{sub em} = 615 nm. This method achieved a 1 ng/ml limit of detection (LOD) with a 100 {mu}l sample solution in a repeated spotting mode. Hyphenation of sorbent extraction and SMTRL was demonstrated using C18. This method is suitable for screening of TC in foods or aqueous solutions and can be extended to other luminescent lanthanide-chelating analytes in physiological or ...
As a result of the large limestone deposits available in Poland, the low cost of reagent acquisition for the largescale technological use and relatively well-documented processes of flue gas desulfurization (FGD) technologies based on limestone sorbent slurry, wet scrubbing desulfurization is a method of choice in Poland for flue gas treatment in energy production facilities, including power plants and industrial systems. The efficiency of FGD using the above method depends on several technological and kinetic parameters, particularly on the pH value of the sorbent (i.e., ground limestone suspended in water). Consequently, many studies in Poland and abroad address the impact of various parameters on the pH value of the sorbent suspension, such as the average diameter of sorbent particles (related to the limestone pulverization degree), sorbent quality (in terms of pure calcium ...
The CO2 adsorption capacity of the low-cost solid sorbents of waste tire char (TC) and chicken waste char (CW) was compared with commercial active carbon (AC) and 5?? zeolite (ZA) using thermogravimetric analysis (TG), pressurized TG, and differential scanning calorimetry (DSC). The sorbents were degassed in a TG up to 150??C to release all gases on the surface of the sample, then cooled down to the designed temperature for adsorption. TG results indicated that the CO2 adsorption capacity of TC was higher than that of CW, but lower than those of AC and ZA. The maximum adsorption rate of TC at 50??C was 0.61% min?1, lower than that of AC, but higher than that of CW, 0.44% min?1. The maximum adsorption rate of ZA at 50??C was 3.1% min?1. When the pressure was over 4?bar, the adsorption rate ...
Phenanthrene and naphthalene sorption isotherms were measured for three different series of kerogen materials using completely mixed batch reactors. Sorption isotherms were nonlinear for each sorbate-sorbent system, and the Freundlich isotherm equation fit the sorption data well. The Freundlich isotherm linearity parameter n ranged from 0.192 to 0.729 for phenanthrene and from 0.389 to 0.731 for naphthalene. The n values correlated linearly with rigidity and aromaticity of the kerogen matrix, but the single-point, organic carbon-normalized distribution coefficients varied dramatically among the tested sorbents. A dual-mode sorption equation consisting of a linear partitioning domain and a Langmuir adsorption domain adequately quantified the overall sorption equilibrium for each sorbent-sorbate system. Both models fit the data well, with r{sup 2} values of 0.965 to 0.996 for the Freundlich model and 0.963 to 0.997 for the ...
A novel sorbent for SO2 removal has been investigated. The sorbent is obtained by conventional incipient wetness impregnation of abandoned biomaterials (straw or dried leaves) with an aqueous solution of Na2CO3. A material with the composition 80 wt % Na2CO3/straw shows a desulfurization activity which is both higher and faster than that of the reference sample Na2CO3/gamma-Al2O3. The breakthrough and stoichiometric SO2 adsorption efficiencies for 80 wt % Na2CO3/straw reach 48.9% and 80.6%, respectively, at a temperature of 80 degrees C. The adsorption efficiencies are almost constant in the temperature range 70 to 300 degrees C. According to IR and XPS analysis the main products observed on the spent sorbent are sulfite below 150 degrees C and sulfate at 300 degrees C. The Na2CO3 in 80 wt % Na2CO3/straw can potentially be recycled by the oxidation of the straw with concomitant reduction of the sulfite species to elemental ...
A detailed study was undertaken to examine the potential of iron oxide present in red mud (a waste product from Bayer's alumina process) as a sorbent for SO/sub 2/ capture by dry process. The other constituents present in the red mud can bring about enhanced utilization of the active component provided they are almost completely inert. The practical use of the process has been explored and a few batchwise cyclic operations of SO/sub 2/ capture and regeneration have also been carried out. A kinetic model of the reaction has been proposed.
The physical structure of a limestone or dolomite to be used in in-bed sulfur capture in fluidized bed boilers has great impact on the efficiency of sulfur capture and sorbent use. Therefore in process optimization and model calculations parameters describing the pore structure of these sorbents must be included. In this study an unreacted shrinking core model with variable effective diffusivity is applied to sulfation test data from a pressurized thermogravimetric apparatus (P-TGA) for various limestone and dolomite samples. The particle size was 250--300 {micro}m for all sorbents. The tests were done under typical conditions for a pressurized fluidized bed combustor, i.e. 850 C or 950 C, 15 bar, and were reported earlier at the 12th International Conference on Fluidized Bed Combustion. At these conditions the limestone remains uncalcined, while the dolomite is half-calcined. The sorbents were ...
Silicon thin film with thickness in range 1000-5300 A deposited on rough Cu foil by a radio frequency magnetron sputtering is used as anode materials for Li-ion rechargeable batteries. The SEM, XRD and TEM analysis reveals that the Si thin film has a floccular nano-sized multi-crystalline structure. Li ions insertion/extraction evaluation is performed mainly with constant current charge/discharge cycling and cyclic voltammetry (CV) at room temperature. The cycleability and reversible discharge capacity are found to depend on the film thickness, and thinner films give larger accommodation capacity. A 3120 A Si film provides a reversible specific capacity over 3500 mA hg{sup -1} with excellent cycleability under 0.5 C charge/discharge rate.
Systems with small sizes show significant changes compared to the bulk system. These changes are of major interest regarding the size reduction of technological applications. The hydrogen-metal system can be used as a model alloy to study small size features: shifted phase boundaries and sloped isotherms are found and, also, new materials structures. Most features can be attributed to surface- and interface contributions as well as to mechanical stress. (Abstract Copyright [2004], Wiley Periodicals, Inc.)
The paper gives results of a study to identify active sites and surface functional groups that may contribute to the absorption of elemental mercury (Hg) by relatively inexpensive calcium (Ca)-based sorbents. The study investigated the formation of chlorine (Cl) sites in CA-based sorbents as well as their role and reactivity in the absorption of Hg. HCl-exposed calcium sulfate dihydrate (gypsum) exhibited a superior Hg sorption capability. Crystalline water molecules on the surface of the gypsum were confirmed to contribute indirectly to Hg uptake. These surface molecules may have absorbed HC1 through hydrogen bond formation between an oxygen atom of a crystalline water molecule and a hydrogen atom of an HCl molecule. Two adjacent, physically absorbed HCl molecules could then trap an Hg molecule through formation of a mercuric-chloride-like molecule. Significant correlations between Cl and Hg uptake by gypsum were noted.
The paper gives results of a study to identify active sites and surface functional groups that may contribute to the absorption of elemental mercury (Hg) by relatively inexpensive calcium (Ca)-based sorbents. The study investigated the formation of chlorine (Cl) sites in CA-based sorbents as well as their role and reactivity in the absorption of Hg. HCl-exposed calcium sulfate dihydrate (gypsum) exhibited a superior Hg sorption capability. Crystalline water molecules on the surface of the gypsum were confirmed to contribute indirectly to Hg uptake. These surface molecules may have absorbed HC1 through hydrogen bond formation between an oxygen atom of a crystalline water molecule and a hydrogen atom of an HCl molecule. Two adjacent, physically absorbed HCl molecules could then trap an Hg molecule through formation of a mercuric-chloride-like molecule. Significant correlations between Cl and Hg uptake by gypsum were noted.
The thermodynamic characteristics of sorption of the isomeric tricyclo[5.2.1.02.6]decane (tetrahydrodicyclopentadiene, TDCPD) molecules were for the first time determined experimentally and by molecular statistical methods under the conditions of gas-adsorption chromatography on graphitized thermal carbon black and gas-liquid chromatography on stationary liquid phases of different polarities (Apiezon L and Carbowax 20M). The effects of the chemical nature of sorbents on the retention of the TDCPD isomers are considered. A procedure for calculating the thermodynamic characteristics of adsorption of molecules with a complex structure is suggested within the framework of the atom-atom approximation of the semiempirical molecular statistical theory of adsorption for the example of isostructura...
Sorption of oxidized and reduced forms of molybdosilicic, molybdophosphoric and molybdovanadophosphoric acids by polyurethane foam based on ethers and esters is studied. On the basis of sorption dependence on solution pH, polyurethane foam type and spectral characteristics of sorbates the suggestion has been made that in the polyurethane foam phase there are two main types of sorbent-sorbate interaction: electrostatic (ion-ion) and with hydrogen bond formation: and it is impossible to determine the contribution of every interaction
A method of simultaneously removing SO.sub.2 and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO.sub.2 and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled.
Batch and dynamic flow biosorption studies were carried out using the waste biomass entrapped in silica-gel matrix for the removal of nickel(II) ions from synthetic solutions and real wastewater. Batch biosorption conditions were examined with respect to initial pH, S/L ratio, contact time, and initial nickel ion concentration. Zeta potential measurements showed that immobilized biosorbent was negatively charged in the pH range of 3.0-8.0. The immobilized biomass was found to possess relatively high biosorption capacity (98.01 mg g{sup -1}), and biosorption equilibrium was established in a short time of operation (5 min). The equilibrium data were followed by Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. Scanning electron microscope analysis was used to screen the changes on the surface structure of the waste biomass after immobilization and nickel(II) biosorption. Sorbent-sorbate interactions were confirmed by Fourier transform infrared ...
The Co-doped BaTiO{sub 3} nanosized powders and ceramics were prepared via the sol-gel process. The powders and ceramics were characterized by methods of XRD, SEM and TEM. The dielectric properties of the ceramics were also determined by these methods. The influence of sintering temperature, sintering time and Co concentration on the microstructure and dielectric properties was discussed. The results revealed that the powders were in nanometer scale (30-50 nm) and were mainly composed of cubic BaTiO{sub 3} phase and small amount of BaCO{sub 3}. After sintering, both the cubic BaTiO{sub 3} and BaCO{sub 3} were transformed into tetrahedron BaTiO{sub 3}. The sintering temperatures of the Co-doped BaTiO{sub 3} ceramics decreased (about 100 deg. C) and the Curie temperatures of the ceramics were then moved to lower temperature. In addition, the dielectric constant of the ceramics doping with Co was higher than that of the pure BaTiO{sub 3} ceramics. The dielectric ...
Nano-sized zinc oxide was synthesized and deposited onto cellulosic fibers using the sol-gel process at ambient temperature. The prepared materials were characterized using several techniques including scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogravimetric analysis. X-ray diffraction studies of the ZnO-coated fiber indicate formation of the hexagonal crystal phase which was satisfactory crystallized on the fiber surface. The electron micrographs show formation of zinc oxide nanoparticles within 10-15 nm in size which have been homogeneously dispersed on the fiber surface. The prepared materials show significant photocatalytic self-cleaning activity, which was monitored by diffuse reflectance spectroscopy. The photoactivity was studied upon measuring the photodegradation of methylene blue and eosin yellowish under UV-Vis irradiation. The photocatalytic activity of the treated fabrics ...
In this study a modified solid state synthesis (auto-ignition method) is used to form nanosized spinel type material LiMg{sub 0.05}Ni{sub 0.45}Mn{sub 1.5}O{sub 4}. This material presents a high voltage plateau at 4.75 V vs. Li/Li{sup +}. Structural and electrochemical characterisations have been performed using a wide range of techniques (TEM, neutron diffraction, galvanostatic measurements, and impedance spectroscopy). Besides, in situ XAS has been performed to monitor the evolution of Ni and Mn oxidation state during Li intercalation. The material presents an ordered cubic spinel structure, good capacity retention upon cycling (131 mAh g{sup -1} at C/10 and 117 mAh g{sup -1} at 1C) and good electronic conductivity (10{sup -6} S cm{sup -1} at RT). The simultaneous presence of Mn{sup 3+}/Mn{sup 4+} in the structure has been investigated and explained by inclusion of disordered nanodomains in the structure. (author)
Nanodimensional powders of cubic copper ferrite are synthesized by two-steps procedure of co-precipitation of copper and iron hydroxide carbonates, followed by mechanochemical treatment. X-ray powder diffraction, Moessbauer spectroscopy and temperature-programmed reduction are used for the characterization of the obtained materials. Their catalytic behavior is tested in methanol decomposition to hydrogen and CO and total oxidation of toluene. Formation of nanosized ferrite material is registered even after one hour of milling time. It is established that the prolonging of treatment procedure decreases the dispersion of the obtained product with the appearance of Fe2O3. It is demonstrated that the catalytic behavior of the samples depends not only on their initial phase composition, but on the concomitant ferrite phase transformations by the influence of the reaction medium. -- Graphical abstract: It is demonstrated that the catalytic behavior of the obtained copper ...
Macromolecular and polyanionic Na(+)-poly(gamma-glutamic acid) (PGA) silver nitrate complex acted as both a metal ion provider and a particle protector to fabricate nanosized silver colloids under chemical reduction by dextrose. The formation and size of particles have been characterized from transmission electron microscopy (TEM), dynamic light scattering analysis and UV-vis spectrophotometer. The results showed that the average particle size was 17.2+/-3.4 to 37.3+/-5.5 nm, apparently depending on the complex concentration. It was found that the rate constant and conversion of silver nanoparticles were proportional to the concentration of PGA. The growth mechanism of nanosized silver colloid was fully discussed. In addition, the in vitro cytotoxicity evaluated by L929 fibroblasts proliferation and antibacterial activity against Gram-positive strain (methicillin-resistant S. aureus (MRSA)) and Gram-negative strain (P. aeruginosa) bacteria have ...
Structural changes of a Ni-P amorphous alloy under focused-ion-beam (FIB) irradiation have been examined using transmission electron microscopy. On the irradiated plane, the formation of crystallographically orientated nanosized crystals (NCs), with the particle size of approximately 10 nm, was observed. A series of electron diffraction analyses have revealed that NCs have a face-centered-cubic (fcc) structure and the following orientation relationships between the NCs and the FIB direction were found. These are, irradiated plane//(111)_f_c_c and FIB direction//_f_c_c.
The thermodynamic characteristics of sorption of the isomeric tricyclo[5.2.1.02.6]decane (tetrahydrodicyclopentadiene, TDCPD) molecules were for the first time determined experimentally and by molecular statistical methods under the conditions of gas-adsorption chromatography on graphitized thermal carbon black and gas-liquid chromatography on stationary liquid phases of different polarities (Apiezon L and Carbowax 20M). The effects of the chemical nature of sorbents on the retention of the TDCPD isomers are considered. A procedure for calculating the thermodynamic characteristics of adsorption of molecules with a complex structure is suggested within the framework of the atom-atom approximation of the semiempirical molecular statistical theory of adsorption for the example of isostructural norbornane molecules. The procedure involves simultaneous variation of geometric parameters and refinement of the parameters that determine the special features of the ...
A technique of producing radioactive isotopes of rare earth elements (r.e.e.) and carrier free "2"4"2Am is suggested. The technique makes use of ''sandwich'' phthalocya=- nine complexes of r.e.e. and americium placed on sorbent. This is a new type of r.e.e. compounds and actinides (C_3_2H_1_6N_8)_2M (M is a metal ion) which are thermally, radiationally and chemically stable, dissolve well in some organic solvents and do not dissolve in water. Radiation and chemically stable activated carbon is used as a sorbent carrier. After irradiation the target is treated by a weakly acid solution or complex-former solution. Radioactive atoms formed due to (n, #gamma#)-reaction and desoleting the complex because of recoil transfer into the solution. When irradiating in the flux of 10"1"3 neutr./cm"2 x s for 1 hour it is possible to produce radioactive isotopes with the yield from 20 to 90%, for example "1"6"0Tb, "1"6"6Ho with enrichment factor > 100 and ...
The goal of this work was to develop a process flow diagram to economically produce a clean-burning fuel from fine Illinois coal. To accomplish this, the process of pelletizing fine coal with calcium hydroxide, a sulfur capturing sorbent, was investigated. Carbonation, which is the reaction of calcium hydroxide with carbon dioxide (in the presence of moisture) to produce a bonding matrix of calcium carbonate, was investigated as a method for improving pellet quality and reducing binder costs. Proper moisture level is critical to allow the reaction to occur. If too much moisture is present in a pellet, the pore spaces are filled and carbon dioxide must diffuse through the water to reach the calcium hydroxide and react. This severely slows or stops the reaction. The ideal situation is when there is just enough moisture to coat the calcium hydroxide allowing for the reaction to proceed. The process has been successfully demonstrated on a pilot-scale as a method of ...
Heat inactivated Aspergillus ustus (Asp), silicon dioxide-nano-powder (N Si), and silicon dioxide nano-powder-combined-heat inactivated Aspergillus ustus (N Si Asp) were used to study the biosorption of Cd(II) from aqueous solutions via batch equilibrium technique. Surface characterization and immobilization of the fungal cells on silicon dioxide-nano-powder were examined and confirmed by using FT-IR and ESM analysis. Cadmium biosorption processes were investigated under the effect of pH, contact time, sorbent dosage and initial metal concentration. The three examined sorbents were found to exhibit maximum mmolg^-^1 capacity values in pH 7.0. The maximum determined cadmium capacity by silicon dioxide-nano-powder (N Si) (600mmolg^-^1) was found higher than that exhibited by the heat inactiv...
This report describes experimental results for the selective removal of strontium and cesium from simulated waste solutions using monosodium titanate (MST) and crystalline silicotitanate (CST)-laden filter cartridges. Four types of ion exchange cartridge media (CST and MST designed by both 3M and POROX{reg_sign}) were evaluated. In these proof-of-principle tests effective uptake of both Sr-85 and Cs-137 was observed. However, the experiments were not performed long enough to determine the saturation levels or breakthrough curve for each filter cartridge. POREX{reg_sign} MST cartridges, which by design were based on co-sintering of the active titanates with polyethylene particles, seem to perform as well as the 3M-designed MST cartridges (impregnated filter membrane design) in the uptake of strontium. At low salt simulant conditions (0.29 M Na{sup +}), the instantaneous decontamination factor (D{sub F}) for Sr-85 with the 3M-design MST cartridge measured 26, ...
The technology developed here will exploit the ability of microorganisms to remove dissolved metals from aqueous solutions. Microbial sorbents for uranium will be immobilized biosorbents will be deployed ex situ within flow-through reactors for the continuous or semicontinuous treatment of recovered wastewaters. The proposed technology will primarily be applied within a pump-and-treat process using immobilized biosorbents for the large-scale, long-term remediation of uranium-laden surface water or groundwater impoundments (environmental restoration). The technology may be equally useful as an ``end-of-pipe`` treatment of process effluents (waste management). Successful operation of this process will achieve immobilization of the targeted waste and accompanying volume reduction.
Purge water from a typical wet flue gas desulfurization system contains myriad chemical constituents and heavy metals whose mixture is determined by the fuel source and combustion products as well as the stack gas treatment process. A well-designed water treatment system can tolerate upstream fuel and sorbent arranged in just the right order to produce wastewater acceptable for discharge. This article presents state-of-the-art technologies for treating the waste water that is generated by wet FGD systems. 11 figs., 3 tabs.
This paper studies the sorption of chlorine complexes of ruthenium (IV) on the graft copolymer of a polyacrylonitrile fiber with poly-2-methyl-5-vinylpyridine (PAN-MVP). The composition of the fiber is illustrated. It is shown that sorption of chlorine complexes of ruthenium (IV) from acid solutions by a pyridine fiber sorbent takes place according to an anion-exchange mechanism and is due to the formation of compounds of the diamine type (Ru(RPy)/sub 2/Cl/sub 4/).
Uranium has varying degrees of oxidation (+4 and +6) and is responsive to changes in the redox potential of the environment. It is deposited at the reduction barrier with the participation of biota and at the sorption barrier under oxidative conditions. Iron (hydr)oxides are the strongest sorbents of uranium. Uranium, being an element of medium biological absorption, can accumulate (relative to thorium) in the humus horizons of some soils. The high content of uranium in uncontaminated soils is most frequently inherited from the parent rocks in the regions of positive U anomalies: in the soils developed on oil shales and in the marginal zone of bogs at the reduction barrier. The development of nuclear and coal-fired power engineering resulted in the environmental contamination with uranium....
Nanomaterials are increasingly being used to modify adhesives used in aerospace and materials applications. Improvements in thermal and mechanical properties have been found by incorporation of small amounts of nanosize materials in to such adhesives. However, the introduction of nanomaterials to adhesives used in civil engineering applications is still a new approach which needs to be explored, especially in retrofitting of structures. This paper presents part of an ongoing research to address the effect of adding nanomaterials to modify a thermosetting adhesive used for bonding carbon fibre reinforced polymer (CFRP) composites to concrete members. Vapour grown carbon fiber (VGCF) was chosen to modify the adhesive. Different concentrations of carbon nanofibres PR-24 XT-LHT were adopted fo...
Abstract A series of polypropylene carbonate (PPC)/ZnO nanocomposite films with different ZnO contents were prepared via a solution blending method. The morphological structures, thermal properties, oxygen permeability, water sorption, and antibacterial properties of the films were investigated as a function of ZnO concentration. While all of the composite films with less than 5 wt % ZnO exhibited good dispersion of ZnO in the PPC matrix, FTIR and SEM results revealed that solution blending did not lead to a strong interaction between PPC and unmodified ZnO. As such, poor dispersion was induced in the composite films with a high ZnO content. By incorporating inorganic ZnO filler nanoparticles, the diffusion coefficient, water uptake in equilibrium, and oxygen permeability decreased as the ...
Nanocrystalline MnFe"2O"4 ferrite was prepared by using autocombustion technique (flash). The microstructure and magnetic properties are studied. The results of XRD and TEM clarified that, this ferrite is nanosized with particle size (39 nm). Magnetic measurements showed a ferromagnetic behavior with T"C = 613 K, the saturation magnetization M"s = 13.71 emu/g, remanent magnetization M"r = 0.1694 emu/g and, coercivity H"c = 25.6 Oe. Natural material, egg white used as an aqueous medium to extend prepare nanoparticles better than other chemical interesting materials.
New results for two types of nano-size silicon, prepared via thermal vapour deposition either with or without a graphite substrate are presented. Their superior reversible charge capacity and cycle life as negative electrode material for lithium-ion batteries have already been shown in previous work. Here the lithiation reaction of the materials is investigated more closely via different electrochemical in situ techniques: Raman spectroscopy, dilatometry and differential electrochemical mass spectrometry (DEMS). The Si/graphite compound material shows relatively high kinetics upon discharge. The moderate relative volume change and low gas evolution of the nano silicon based electrode, both being important points for a possible future use in real batteries, are discussed with respect to a standard graphite electrode. (author)
Nanosized CaSnO{sub 3} is synthesized by a hydrothermal process and characterized by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The SEM observation shows the sample has a porous flowerlike morphology. The electrochemical results exhibit that the stable and reversible capacity of 547 mAh g{sup -1} is obtained after 50 cycles at 60 mA g{sup -1} (0.1 C) and the corresponding charge capacity is determined to be 316 mAh g{sup -1} at the current density of 2.5 C. Cyclic voltammetry and electrochemical impedance spectroscopy data are analyzed to complement the galvanostatic results. The observed excellent performance is attributed to the porous structure and large surface area of flowerlike CaSnO{sub 3}.
We have investigated the effect of manganese (Mn) doping on properties of nanosized biphasic calcium phosphate powders and their dense bodies. Manganese levels of 0.6, 1.3, 1.9, 4.3, 7.0 and 11.9at.% were successfully incorporated into biphasic calcium phosphate via a sol-gel route. The prepared powders were calcined at temperatures of 500-1200^oC. The X-ray diffraction analysis revealed that a mix phase comprising of hydroxyapatite and @b-tricalcium phosphate were present, however the content of each phases in the structure was affected by the Mn content. The studies found that the largest portion of @b-tricalcium phosphate was detected at 4.3at.% Mn doping. The incorporation of Mn has also greatly increased the crystallinity of the biphasic calcium phosphate powder due to progressive den...
We explore a novel phenomenon of focused ion beam (FIB) induced bending of carbon nanopillars or cantilever structures. The bending occurs towards the ion beam during scanning. The explanation of this bending has been sought on the basis of a model which considers temperature rise and gradients caused by the impinging ion beam. The process is controllable and reversible, which makes it highly suitable for in situ manipulation to make desired 3D shapes by the piecewise bending of the nanopillars and cantilever structures during their fabrication using electron beam or FIB chemical vapor deposition (EB-CVD or FIB-CVD). Its usefulness in the fabrication of nanosize mechanical components has been demonstrated by making a branch structure from a single cantilever.
Bio-inspired silver nanoparticles were synthesized with the aid of a novel, non-toxic, eco-friendly biological material namely, banana peel extract (BPE). Boiled, crushed, acetone precipitated, air-dried peel powder was used for reducing silver nitrate. Silver nanoparticles were formed when the reaction conditions were altered with respect to pH, BPE content, concentration of silver nitrate and incubation temperature. The colorless reaction mixtures turned brown and displayed UV-visible spectra characteristic of silver nanoparticles. Scanning electron microscope (SEM) observations revealed the predominance of silver nanosized crystallites after short incubation periods. When the reaction mixtures were incubated for 15 days, some micro-aggregates were also observed. Energy dispersive spectr...
Scanning ion microscopy with polarization analysis (SIMPA) is used to study the spin-resolved surface magnetic structure of nano-sized magnetic systems. SIMPA is utilized for in situ topographic and spin-resolved magnetic domain imaging as well as for focused ion beam (FIB) etching of desired structures in magnetic or non-magnetic systems. Ultra-thin Co films are deposited on surfaces of Si(1 0 0) substrates, and ultra-thin, tri-layered, bct Fe(1 0 0)/Mn/bct Fe(1 0 0) wedged magnetic structures are deposited on fcc Pd(1 0 0) substrates. SIMPA experiments clearly show that ion-induced electrons emitted from magnetic surfaces exhibit non-zero electron spin polarization (ESP), whereas electrons emitted from non-magnetic surfaces such as Si and Pd exhibit zero ESP, which can be used to calibrate sputtering rates in situ. We report on new, spin-resolved magnetic microstructures, such as magnetic 'C' states and magnetic vortices, found at surfaces of FIB patterned ...
The treatment of peat with the solutions of phosphoric, citric, and oxalic acids in concentrations of 10???4 and 10???2 mol/l at solid phase to liquid ratios of 1: 2.5 and 1: 5 increased the absorption of ammonia by 6.4???39.7%. The absorption of ammonia was higher than the concentration of doping ion-exchange groups by a factor of 5???2000. With the use of EPR and IR spectroscopy, it was found that this phenomenon was caused by the transformation of polyconjugation systems as a result of the interaction of acids with the organic matrix of peat by a macrocoordination mechanism, which also improved the technological characteristics of the resulting sorbents. The absence of the destruction of organic matter with the use of low concentrations of weak acids makes it possible to use these sorbe...
Homidium bromide and isometamidium chloride are used extensively in the treatment of bovine trypanosomiasis in Africa, but no specific and sensitive method to detect the drug in plasma has been published yet. Comparing the methods of other investigators it was found that they could not overcome the protein binding of these drugs which reduced the available and determined drug to 10% of the real concentrations. These techniques overcome the protein binding by enzyme digestion and an alteration of the pH before adding the sample directly on clean-up columns. Drug recover rates above 80% were obtained. For the detection, the HPLC was employed using a C18 reversed phase analytical column and UV detection, determining both drugs as intact molecules. (author).
The design of a reaction cell which permits the investigation of the sorption kinetics of microcomponents without separation of the phases under automated condition has been described. The use of thin-layer inorganic sorbents obtained by depositing films of a sorbing substance from aqueous solutions on flat substrates of small thickness makes it possible to determine the extent of sorption even at small values in the case of /beta/ emitters with a low energy and /alpha/ emitters. Detailed observation of the kinetics of isotopic exchange in the CdS-/sup 115m/Cd-HNO/sub 3/ system has made it possible to reveal at least four stages in the process during the time of observation.
A novel wastewater treatment technique has been investigated, for reactive dye removal, in batch kinetic systems. These experimental studies have indicated that charred dolomite has the potential to act as an adsorbent for the removal of Brilliant Red reactive dye from aqueous solution. The effect of initial dye concentration, adsorbent mass:liquid volume ratio, and agitation speed on dye removal have been determined with the experimental data mathematically described using empirical external mass transfer and intra-particle diffusion models. The experimental data show conformity with an adsorption process, with the removal rate heavily dependent on both external mass transfer and intra-particle diffusion. PMID:12691893
The thermodynamic characteristics of adsorption (the Henry constant, the heat and entropy of adsorption) of amino acids associates with acetic, trifluoroacetic, nonafluoropentanoic acids and formamide with different values of hydrogen bond lengths and various conformations on a graphitized thermal carbon black (GTCB) were calculated. The experimental results, as the Henry constant, lnK1, and the differences in the molar Gibbs energies, d(DG), obtained by a high performance liquid chromatography (HPLC) on a carbon sorbent Hypercarb, were compared with the values of thermodynamic characteristics of adsorption of the amino acids on the GTCB surface calculated by a molecular-statistical method. A satisfactory correlation was observed between the experimental and calculated values with a coeffi...
Using methods of the Moessbauer spectroscopy, scanning electron microscopy, and thermodynamic analysis of phase formation in silicate multi-component melts, the detailed study of composition, morphology, and properties of fly ash microspheres resulting from combustion of three coals (Irsha-Borodinskii, Kuznetskii and Ekibastuzskii) was carried out. About 60 microspherical products with an iron content of 2-94 wt.% Fe_2O_3 were obtained. The ranges of microsphere composition, suitable for liquid radioactive waste solidification in the forms of iron phosphate (36-94 wt.% Fe_2O_3) and aluminosilicate (2-20 wt.% Fe_2O_3) ceramics were determined. The possibility of producing porous materials and specific microspherical sorbents, based on coal fly ash cenospheres and their application for mobilisation of liquid radioactive waste solidification was demonstrated. (author)
In this work, a water-soluble polymer, polyethylenimine (PEI) was used for the simultaneous separation and preconcentration of trace Cu and Mn prior to their determination by flame atomic absorption spectrometry. For this purpose, the sample and the PEI solution were mixed and the metal-bound polymer was precipitated by adding acetone. The precipitate was separated and dissolved in a minimum amounts of water and aspirated into a flame AAS. By increasing the ratio of the volumes of sample to water used in dissolving the precipitate, the analyte elements were concentrated as needed. The sorption is quantitative in the pH ?6. Detection limits were 5.2 ?g/L for Cu and 5.4 ?g/L for Mn. This method is simple, fast and precise.
Artificial selection and experimental evolution document natural selection under controlled conditions. Collectively, these techniques are continuing to provide fresh and important insights into the...Full Text Available
The theoretical and experimental investigation of the mechanism of SO2 and H2S removal by CaCO3 -based sorbents (limestones and dolomites) in pressurized uidized-bed coal combustors (PFBC) and high pressure gasiers, respectively, is the main objective of this study. It is planned to carry out reactivity evolution experiments under simulated high pressure conditions or in high pressure thermogravimetric and, if needed, uidized- bed reactor (high pressure) arrangements. The pore structure of fresh, heat-treated, and half-calcined solids (dolomites) will be analyzed using a variety of methods. Our work will focus on limestones and dolomites whose reaction with SO2 or H2S under atmospheric conditions has been studied by us or other research groups in past studies. Several theoret- ical tools will be employed to analyze the obtained experimental data including a variable diusivity shrinking-core model and models for diusion, reaction, and structure evolution in ...
Coal fired combined cycle power systems will be a sufficient way to increase the efficiency of coal combustion. However, combined cycle power systems require a reliable hot gas cleanup. Especially alkali metals, such as sodium and potassium, can lead to hot corrosion of the gas turbine blading if they condensate as sulphates. The actual work deals with the release and sorption of alkali metals in coal fired combined cycle power systems. The influence of coal composition, temperature and pressure on the release of alkali species in coal combustion was investigated and the relevant release mechanisms identified. Alumosilicate sorbents have been found that reduce the alkali concentration in the hot flue gas of the Circulating Pressurized Fluidized Bed Combustion 2{sup nd} Generation (CPFBC 2{sup nd} Gen.) at 750 C to values sufficient for use in a gas turbine. Accordingly, alumosilicate sorbents working at 1400 C have been found for the ...
Carbothermal reduction-nitridation (CRN) of SiO_2 is an attractive method for manufacturing Si_3N_4 powders with controlled grain morphology. Moreover, #beta#-sialon powders could also be synthesized from either pure powder mixtures or some inexpensive raw minerals by CRN. The resultant powders have shown some advantages, especially in manufacturing sialon products at low cost. However, there have been only a few works on preparing #alpha#-sialon powders. In this work, Ca-#alpha# sialon powder was synthesized by CRN of a SiO_2-Al_2O_3 and CaCO_3 powder mixture An unusual morphology of hollow balls of 200 to 500nm with many nano size #alpha#-sialon particles of 10 to 30nm was identified from the resultant Ca-#alpha# sialon powders. This has never been previously reported for sialon ceramics. It was consequently confirmed that the morphologies of the products were clearly related to the intermediate products appearing during CRN reaction. Copyright (2000) The Australian Ceramic Society
Carbon nanofiber (CNF) supported cobalt oxide composites as high-capacity anode materials were prepared through a facile, effective method for potential use in rechargeable lithium-ion batteries. The effects of the calcining temperature on the crystallinity, grain size, specific surface area of Co{sub 3}O{sub 4} and phase transformation from Co{sub 3}O{sub 4} to CoO were studied in detail. Both the specific surface area and CNF content in CNF-cobalt oxide composites strongly affect the electrochemical performance of these series composites. The CNF-Co{sub 3}O{sub 4} composite with 24.3% CNF pyrolyzed at 500 deg. C in Ar shows an excellent cycling performance, retaining a specific capacity of 881 mAh g{sup -1} beyond 100 cycles. Homogeneous deposition and distribution of nanosized Co{sub 3}O{sub 4} particles on the surface of CNF can stabilize the electronic and ionic conductivity as well as the morphology of Co{sub 3}O{sub 4} phase, which may be the main reason for ...
Carbon nanofiber (CNF) supported cobalt oxide composites as high-capacity anode materials were prepared through a facile, effective method for potential use in rechargeable lithium-ion batteries. The effects of the calcining temperature on the crystallinity, grain size, specific surface area of Co{sub 3}O{sub 4} and phase transformation from Co{sub 3}O{sub 4} to CoO were studied in detail. Both the specific surface area and CNF content in CNF-cobalt oxide composites strongly affect the electrochemical performance of these series composites. The CNF-Co{sub 3}O{sub 4} composite with 24.3% CNF pyrolyzed at 500{sup o}C in Ar shows an excellent cycling performance, retaining a specific capacity of 881 mAh g{sup -1} beyond 100 cycles. Homogeneous deposition and distribution of nanosized Co{sub 3}O{sub 4} particles on the surface of CNF can stabilize the electronic and ionic conductivity as well as the morphology of Co{sub 3}O{sub 4} phase, which may be the main reason ...
Ultraviolet (UV) photoirradiation of Ag(I) compounds in the presence of an aqueous Triton X-100 solution has been exploited for the first time to prepare reproducible yellow silver hydrosol. The evolution of nanosized silver particles has been examined critically under the influence of different anions/ligands. Hence, time dependent evolution of silver hydrosol from different silver compounds in micelle via photochemical reduction is observed. Anions/ligands of precursor salts have been found to show profound influence (due to electron scavenging property, solubility, stability etc.) on the evolution route and efficiency of photochemical reduction of Ag(I) to Ag(O) in micelle and thereby classification of silver compounds becomes possible. Kinetic results reveal that the formation of silver particles proceeds via autocatalytic growth mechanism. The observed variation in rate constant values for the evolution of nanoparticles from different silver compounds have ...
Spherical nanostructured Si/C composite was prepared by spray drying technique, followed by heat treatment, in which nanosized silicon and fine graphite particles were homogeneously embedded in carbon matrix pyrolyzed by phenol formaldehyde resin. Cyclic voltammetry tests showed two pairs of redox peaks corresponding to lithiation and delithiation of Si/C composite. The Si/C composite exhibited a reversible capacity of 635 mAh g"-"1 and good cycle performance used in lithium ion batteries. To improve cycle performance of this Si/C composite further, the carbon-coated Si/C composite was synthesized by the second spray drying and heat treatment processing. The cycle performance of carbon-coated Si/C composite was improved significantly, which was attributed to the formation of stable SEI passivation layers on the outer surface of carbon shell which protected the bared silicon from exposing to electrolyte directly.
TaC and TaC-1wt.% B4C powders were consolidated using spark plasma sintering (SPS) at 1850^oC and varying pressure of 100, 255 and 363MPa. The effect of pressure on the densification and grain size is evaluated. The role of nano-sized B4C as sintering aid and grain growth inhibitor is studied by means of XRD, SEM and high resolution TEM. Fully dense TaC samples were produced at a pressure of 255MPa and higher at 1850^oC. The increasing pressure also resulted in an increase in TaC grain size. Addition of B4C leads to an increase in the density of 100MPa sample from 89% to 97%. B4C nano-powder resists grain growth even at high pressure of 363MPa. The formation of TaB2/Carbon at TaC grain boundaries helps in pinning the grain boundary and inhibiting grain growth. The effect of B4C addition on...
In this study, silver nanoparticles were formed on a natural macroporous matrix, the stem of rice-paper plant, by reducing Ag{sup +} in aqueous solution through in situ processing without using any other stabilizers. The pores of the matrix, with their size of about 100 {mu}m, were thought to act as reaction compartments for the nucleation and growth of silver nanoparticles, and the control of nucleation of silver crystal during the reduction reaction was found to be important to the successful formation of nanosized silver particles onto the matrix. The diameter and amount of resultant silver particles can be controlled by changing the reaction conditions. Under optimized conditions, the content of silver particles in the matrix can reach as high as 1.8 wt% with the particle diameters being kept below 100 nm. The anti-microbial activities in terms of minimum inhibitory concentration (MIC) for the silver nanoparticle composites against Escherichia coli and Candida ...
We evaluated the use of a novel gene porter (Den123-a nontoxic self-assembled dendritic spheroidal nanoparticle made of biodegradable monomers), aiming to enhance and improve the desired immune response in protection from allergy. Footpad DNA immunization in Balb/c mice was done three times using the Bet v 1a gene with or without Den123 with 2-week intervals followed by sensitization with rBetv1 (5mg) in alum twice in a weekly interval. Different doses of pCMV-Betv1 were used (10mg and 100mg). The protective role of different formulations was evaluated by measuring the IgG1, IgG2a and IgE antibody production, cytokine release of isolated splenocytes and b-hexosaminidase release from the RBL cells. Higher and increasing ratios of IgG2a/IgG1 were seen in mice which received plasmids in combi...
The synthesis of narrowly dispersed nanocrystalline TiO_2 was investigated with a surfactant aided solvothermal synthetic method in toluene solutions. When a sufficient amount of titanium isopropoxide, Ti[OCH(CH_3)_2]_4 (TIP), was added to the solution, the shapes of TiO_2 nanoparticles changed from spheres to rods. The aggregated microstructures of the nano-sized TiO_2 in systems of spheres, rods, and mixtures of spheres and rods was studied using TEM. The morphological shape of the aggregation was described in terms of the fractal dimensions. We used a box-counting method to get the fractal dimension of these systems. The fitted fractal dimensions for spheres, sphere/rod mixtures, and rods are D = 1.54, D = 1.81, and D = 1.89, respectively. The fractal dimension changed from 1.54 to 1.9 with the TIP/toluene ratio, indicating that the growth mechanism for aggregations showed different behaviors.
Ferroelectric barium strontium titanate (Ba0.7Sr0.3TiO3)(BST) thin films have been prepared from barium 2-ethylhexanoate [Ba[CH3(CH2)3CH(C2H5)CO2]2], strontium 2-ethylhexanoate [Sr[CH3(CH2)3CH(C2H5)CO2]2] and titanium(IV) isopropoxide [TiOCH(CH3)2]4 precursors using a modified sol-gel technique. The precursor except [TiOCH(CH3)2]4 were synthesized in the laboratory. Transparent and crack-free films were fabricated on pre-cleaned quartz substrates by spin coating. The structural and optical properties of films annealed at different temperatures have been investigated. The as-fired films were found to be amorphous that crystallized to the tetragonal phase after annealing at 550degreeC for 1h in air. The lattice constants "a" and "c" were found to be 3.974A and 3.990A, respectively. The grain...
For rational use of energy resources, the process technology which allows harmonization and multiplication of conflicting characteristics was developed for development of new ceramic system materials. This paper summarizes the result in fiscal 1997. On a structural reaction process among creation technologies of ultra-reliable structure, study was made on structure control and hot-working technology through atmosphere control in ceramics synthesis. On basic technology for analysis and evaluation, study was made on the effect of particle bridging on strengthening and toughening of ceramic materials. Study was also made on a toughness expression mechanism, FEM model analysis of particle bridging, and crack growth resistance of ceramics. On control of solid solution precipitation, new alumina ceramics with high strength, hardness and wear resistance was obtained by transgranularly precipitating nano-size particles from a fine-grain high-density matrix through an ...
The present article describes a novel synthesis route for nano-sized goethite ({alpha}-FeOOH) using hydrazine sulphate as an additive. The X-ray diffraction (XRD) peaks of synthesized powder matched well with those of {alpha}-FeOOH. Transmission electron microscopy (TEM) showed the particles of irregular shape in the range of 1-10 nm. Batch adsorption experiments for fluoride uptake were performed to study the influence of various experimental parameters such as contact time (10 min to 7 h), initial fluoride concentration (10-150 mg L{sup -1}), pH (2-11.6) and the presence of competing anions. The time data fitted well to pseudo-second-order kinetic model. The fluoride removal passed through broad maxima in pH ranges of 6-8. High adsorption capacity of 59 mg g{sup -1} goethite was obtained. The isothermic data fitted well to Freundlich model. The presence of other ions namely chloride and sulphate adversely affected fluoride removal. Fluoride from contaminated ...
This work has been undertaken with a view to study the effect of lanthanum content on properties of PLZT ceramics. The polycrystalline complex compounds of PLZT with Pb{sub 1-x}La{sub x}(Zr{sub 0.40}Ti{sub 0.60}){sub 1-x/4}O{sub 3}, +10% PbO formula were prepared from the nano-size individual oxides powders by hot-pressed process. Transparent PLZT (x/40/60) bulk ceramics with pure tetragonal phase was obtained. The studies of the microstructures, dielectric and ferroelectric properties of the ceramics were carried out. The experiment results showed that when La content increased from 7 to 13 mol.%, the grain size increased from 2 to 7 {mu}m. La content also effects the dielectric property obviously, the dielectric constant increased with La content increasing. Moreover, the ferroelectric properties are sensitive to the variation of La content.
This work has been undertaken with a view to study the effect of lanthanum content on properties of PLZT ceramics. The polycrystalline complex compounds of PLZT with Pb_1_-_xLa_x(Zr_0_._4_0Ti_0_._6_0)_1_-_x_/_4O_3, +10% PbO formula were prepared from the nano-size individual oxides powders by hot-pressed process. Transparent PLZT (x/40/60) bulk ceramics with pure tetragonal phase was obtained. The studies of the microstructures, dielectric and ferroelectric properties of the ceramics were carried out. The experiment results showed that when La content increased from 7 to 13 mol.%, the grain size increased from 2 to 7 #mu#m. La content also effects the dielectric property obviously, the dielectric constant increased with La content increasing. Moreover, the ferroelectric properties are sensitive to the variation of La content.
The magnetic separation technology using sub-microsized ferromagnetic particle is indispensable in many areas of medical biosciences. For example, ferromagnetic particles (200-500 nm) are widely used for cell sorting in stem cell research with the use of cell surface-specific antigens. Nanosized ferromagnetic particles (10-20 nm) have been suggested as more suitable in drug delivery studies given their efficiency of tissue penetration, however, the magnetic separation method for them has not been established. One of the major reasons is that magnetic force acting on the object particles decreases drastically as a particle diameter becomes small. In this study, magnetic force acting on the targets was enhanced by the combination of superconducting magnet and the filter consisting of ferromagnetic particle. By doing so, we confirmed that Fe{sub 3}O{sub 4} of 20 nm in diameter was trapped in the magnetic filter under an external magnetic field of 0.5 T. Fe{sub 3}O{sub ...
Olfactory tract has been demonstrated to be an important portal for inhaled solid nanoparticle transportation into the central nervous system (CNS). We have previously demonstrated that intranasally instilled Fe_2O_3 nanoparticles could transport into the CNS via olfactory pathway. In this study, we investigated the neurotoxicity and size effect of repeatedly low-dose (130 #mu#g) intranasal exposure of nano- and submicron-sized Fe_2O_3 particles (21 nm and 280 nm) to mice. The biomarkers of oxidative stress, activity of nitric oxide synthases and release of monoamine neurotransmitter in the brain were studied. Our results showed that significant oxidative stress was induced by the two sizes of Fe_2O_3 particles. The activities of GSH-Px, Cu,Zn-SOD, and cNOS significantly elevated and the total GSH and GSH/GSSG ratio significantly decreased in the olfactory bulb and hippocampus after the nano- and submicron-sized Fe_2O_3 particle treatment (p < 0.05). The ...
Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO{sub 2} (m-CeO{sub 2}) and also 1.5% and 3.0% nano-size CeO{sub 2} (n- CeO{sub 2}) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO{sub 2} laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO{sub 2} powders to NBA (m- and n- CeO{sub 2} /NBA) have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (P= 2.0 kW, V= 180 mm min{sup -1}) by adding 1.5% n- CeO{sub 2}. In addition to the primary phases of {gamma}-Ni, Cr{sub 23} C{sub 6} and Ni{sub 3} B in the Ni-base alloy coating, CeNi{sub 3} was formed in Ni-base alloy coatings with both n- CeO{sub 2} and m-CeO{sub 2} particles, and CeNi{sub 5} appeared in the coating upon decreasing the size of CeO{sub 2} particles. Well-developed dendrites were ...
Atrazine and phenanthrene (Phen) sorption by nonhydrolyzable carbon (NHC), black carbon (BC), humic acid (HA) and whole sediment and soil samples was examined. Atrazine sorption isotherms were nearly linear. The single-point organic carbon (OC)-normalized distribution coefficients (K_O_C) of atrazine for the isolated HA1, NHC1 and BC1 from sediment 1 (ST1) were 36, 550, and 1470 times greater than that of ST1, respectively, indicating the importance of sediment organic matter, particularly the condensed fractions (NHC and BC). Similar sorption capacity of atrazine and Phen by NHC but different isotherm nonlinearity indicated different sorption domains due to their different structure and hydrophobicity. The positive relationship between (O + N)/C ratios of NHC and atrazine log K_O_C at low concentration suggests H-bonding interactions. This study shows that sediment is probably a less effective sorbent for atrazine than Phen, implying that atrazine applied in ...
The efficiency of the synthesized zeolite NaY from rice husk ash (RHA) in the removal of Cr(III) from aqueous solution was studied. Zeolite NaY was synthesized from RHA via seeding technique and the identification of its structure was done by X-ray Diffraction (XRD) technique and the elemental analysis was carried out by X-ray Fluorescence (XRF). The physicochemical properties which were related to the use of the zeolite NaY as a sorbent was also investigated. The synthesized zeolite NaY has higher cation exchange capacity (CEC) than the commercial zeolite NaY due to the higher amount of sodium content in the synthesized as well as the lower ratio of silica to alumina. The synthesized zeolite NaY together with the commercial one as comparison was used in the sorption of the Cr(III) in aqueous solution by batch sorption experiments. The kinetic study showed that the Cr(III) uptake by both zeolites were based on the pseudo second order model. Synthesized zeolite NaY ...
This report describes in detail the First Generation Duct Injection Model developed for the analysis of the fundamental processes of flue gas desulfurization by sorbent injection. The model is a two- and three-dimensional, multiphase reacting flow analyzer using computational fluid dynamics methods. The gaseous phase is solved in an Eulerian frame while the droplets or particles are tracked in a Lagrangian frame. The model has an associated preprocessor which allow easy problem set up by the use without in-depth knowledge of computational fluid dynamics. The aerodynamics of the First Generation Duct Injection Model have been successfully validated with a number of test cases for which experimental data are available. Data from the Meredosia pilot plant humidification tests have been used to validate the gas and droplet dynamics of the model with good agreement. Comparison of SO{sub 2} removal results using the present model (with one injector) and the ...
Primary objective was to investigate the effects of pore structure on capacity of porous metal oxides for removal of SO[sub 2] from power plant fuel gas and H[sub 2]S from hot coal gas. During this period, a comparative study was carried out on the direct reaction with H[sub 2]S and SO[sub 2] of the three limestones used as CaO precursors: Greer limestone, Georgia marble, and Iceland spar calcite. Sulfation was carried out at 750 and 850 C in a thermogravimetric analysis system under simulated high pressure (enough CO[sub 2] to prevent decomposition of CaCO[sub 3]). Results are presented as conversion vs time graphs. Mercury penetration and gas adsorption were used to analyze the structure. Activation energies and effective diffusivities were determined. A variable diffusivity shrinking-core model was used to analyze the data. In the future, this limestone study will be completed, and a study on supported CuO sorbent will be started.
The development and testing of novel control technologies and advanced adsorbent materials continue to be active areas of research. In the present study, Hg capture using adsorbent material derived from the bauxite residue (red mud) from two North American refineries was studied. The red mud, seawater-neutralised red mud, and acid-treated red mud were evaluated for their mercury adsorption capacity and compared with other, more conventional sorbent materials. Two different seawater-neutralised red mud (Bauxsol) samples were treated with HCl and HBr in an effort to increase the mercury sorption capacity. In all cases, the acid treatment resulted in a significant increase in the total surface area and an increase in the total pore volume. The fixed-bed mercury capture experimental results showed that the HBr activation treatment was very effective at increasing the mercury capture performance of both Bauxsol samples whereas the HCl treatment had no effect on the ...
Fundamental investigations into the biosorption of environmentally relevant heavy metals were carried out with different microbial adsorbents, and processes were proposed for industrial effluents. In order to improve the technology of biosorption processes, attempts were made to improve the sorption efficiency of biological sorbents, and investigations were carried out on the immobilisation of biological adsorbents. (orig.) [Deutsch] Es wurden Grundlagenuntersuchungen zur Biosorption von umweltrelevanten Schwermetallen mit verschiedenen mikrobiellen Adsorbentien durchgefuehrt und an technischen Abwaessern Technologievorschlaege erarbeitet. Zur Verbesserung der Technologie von Biosorptionsprozessen wurden Moeglichkeiten der Steigerung der Sorptionsleistung von Biosorbentien erarbeitet und Untersuchungen zur Immobilisierung der biologischen Adsorbentien durchgefuehrt. (orig.)
Limestone-based sorbents are used extensively in utility boilers and tail-gas desulfurization units to remove sulfur oxides formed during the combustion of fossil fuels. Such units generate {approximately}20 million tons of flue-gas desulfurization (FGD) wastes in the U.S. annually, the bulk of which ({approximately}95%) are discarded in landfills or holding ponds. However, a significant portion of the Ca in these materials is not sulfated (remains as CaO or Ca(OH){sub 2}), particularly in units that generate dry wastes. When hydrated, such wastes exhibit a strong affinity to absorb acid gases at ambient temperature. This study represents a continuation of previously reported CO{sub 2}-absorption studies and includes more recent work on the absorption of H{sub 2}S and NO. Ten FGD-waste samples along with a control fly ash were examined. Absorption capacities, the role of available calcium and particle size, and mineralogic changes in the wastes following exposure ...
The Institute of Gas Technology (IGT) has conducted a fundamental research program to determine the technical feasibility of a process concept that involves pressurized CO{sub 2}-coal gasification followed by a high-temperature CO{sub 2} removal step, using a MgO-based sorbent. To investigate a hot-CO{sub 2}-removal process, various MgO-containing materials were tested for their reactivity and capacity for removing CO{sub 2} from hot gas streams in a high-pressure thermobalance. No naturally-occurring materials were found to be acceptable, but a KOH-promoted magnesia was found to be sufficiently active for CO{sub 2} removal and to have a good capacity for CO{sub 2} absorption. Tests were conducted at pressures and temperatures in the ranges of 100--300 psig and 850{degree}--1170{degree}F. The CO{sub 2} absorption/desorption cycle was shown to be achievable by a simple pressure-swing operation between 0 and 315 psi CO{sub 2} partial pressure. 4 refs., 8 figs., 2 ...
The magnetically fluidized bed (MFB) was used as the reactor in a novel semidry flue gas desulfurization (FGD) process to achieve high desulfurization efficiency. Experiments in a laboratory-scale apparatus were conducted to reveal the effects of approach to adiabatic saturation temperature, Ca/S molar ratio and applied magnetic field intensity on SO(2) removal. Results showed that SO(2) removal efficiency can be obviously enhanced by decreasing approach to adiabatic saturation temperature, increasing Ca/S molar ratio, or increasing applied magnetic field intensity. At a magnetic field intensity of 300Oe and a Ca/S molar ratio of 1.0, the desulfurization efficiency (excluding desulfurization efficiency in the fabric filter) was over 80%, while spent sorbent appeared in the form of dry powder. With the SEM, XRD and EDX research, it can be found that the increase of DC magnetic field intensity can make the surface morphology on the surface of the ferromagnetic ...
Natural, formaldehyde-treated and copolymer-grafted orange peels were evaluated as adsorbents to remove lead ions from aqueous solutions. The optimum pH for lead adsorption was found to be pH 5. The adsorption process was fast, reaching 99% of sorbent capacity in 10 min for the natural and treated biomasses and 20 min for the grafted material. The treated biomass showed the highest sorption rate and capacity in the batch experiments, with the results fitting well to a pseudo-first order rate equation. In the continuous test with the treated biomass, the capacity at complete exhaustion was 46.61 mg g{sup -1} for an initial concentration of 150 mg L{sup -1}. Scanning electronic microscopy and energy dispersive X-ray spectroscopy indicated that the materials had a rough surface, and that the adsorption of the metal took place on the surface. Fourier transform infrared spectroscopy revealed that the functional groups responsible for metallic biosorption were the -OH, ...
Limestone slurry needs to move efficiently through a complex process, meaning that selecting the right pumps and valves is critical. The article discusses factors to consider in selecting pumps and values for flue gas desulfurization process in coal-fired power plants. 2 photos.
Economic and performance criteria that should be used in the selection of a scrubber system are presented. Selection should be based on the type of emissions put out by a plant and the removal efficiency required by pollution control standards. Costs and efficiencies for 10 different scrubber systems are reported. (10 diagrams)
Batch interaction experiments were performed under aerobic conditions to characterize the adsorption behavior and valence speciation of CoEDTA complexes (equimolar at 10 -5 mol/L) in a series of Pliocene subsurface sediments containing various amounts of Fe and Mn oxides. The experiments were performed in 0.003 mol/L Ca(ClO 4 ) 2 with a solids concentration of 500 g/L at variable pH (4-9) and at the natural pH of the sediments (pH = 8.3). Three of these subaerial sediments (Ringold 1, 2, 3) contained significant quantities of extractable Fe and Mn, while the fourth (Ringold 4) was virtually devoid of sesquioxide precipitates. Microscopic and mineralogic analyses of the most heavily encrusted material (Ringold 2) showed that the oxides existed as intergrain cements and contained crystalline goethite and rancieite/todorokite. Adsorption on a synthetic analog sorbent (0.6 mass % ferrihydrite-coated sand) over a range in pH showed that, while both Co(II)EDTA 2- and ...
BackgroundFeature selection is an important pre-processing task in the analysis of complex data. Selecting an appropriate subset of features can improve classification or clustering...Full Text Available
The development of several DDT-resistant strains of Anopheles atroparvus is described. They were selected by larval treatment only (RL), selection of larval and adult females (RLAF),...Full Text Available
Sep 21, 2006 ... NASA has selected Air Products and Chemicals, Inc., Allentown, Pa., to design, furnish and install a plant to produce liquid nitrogen for ...
This paper reviews our simulation study by numerical calculation based on two-, three- and multi-grain-size models on WC grain growth in fine grained WC-Co hardmetal doped with VC. The study aimed to presume or predict the following: (1) the cause and conditions for the abnormal grain growth which occurs in some cases in the fine grained hardmetal prepared from fine WC powders with mean grain size below about 0.2{mu}m, and (2) how the mean grain size of the hardmetal varies with decreasing mean grain size of the WC starting powder to 0.1 pm or nano-meter size. The calculation results by these three kinds of models suggested the following, respectively: (1) the occurrence of the abnormal grain growth is generally substantial for WC starting powder with bimodal size-distribution and mean gram size below 0.1 - 0.2{mu}m, and not due to the non-uniform distribution of the grain growth inhibitor, (2) the introduction of middle grains caused the disappearance of small (fine) grains during ...
The purpose of this memo is to give an update on our work on ceramic laser materials--feasibility proposal 04-FS-006. Transparent ceramic materials have several major advantages over single crystals in laser applications including, ease and robustness of manufacturing, large apertures, design flexibility, fracture toughness, high activator concentrations, uniformity of composition, no residual stress, and others discussed in the proposal. After a decade of working on making transparent YAG:Nd in 1995 Japanese workers demonstrated samples for the first time that performed as well in lasers as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. The highlights and executive summary of our work to date are: (1) Ordered a slab of transparent YAG:Nd from Konoshima Chemical Co. for ...
The paper reports on the results of a study of the synthesis conditions effects on magnetic and transport properties of nanosized layers of high-T{sub c} diluted magnetic semiconductors (DMS), such as Ge:Mn, Si:Mn and Si:Fe, fabricated by laser-plasma deposition over a wide range of the growth temperature, T{sub g}=(20-550) deg. C on single-crystal GaAs or Al{sub 2}O{sub 3} substrates. Ferromagnetism of the layers was detected by measurement data of the magneto-optical Kerr effect, anomalous Hall effect, negative magnetoresistance and ferromagnetic resonance (FMR) at 5-500 K. The optimum growth temperature, T{sub g}, for Si:Mn/GaAs layers with T{sub c}{approx}400 K is shown to be about 400 deg. C. The Si:Mn/Al{sub 2}O{sub 3} layers with 35% of Mn have the metal-type of conductivity with manifestation of magnetization up to room temperature. Different types of uniformly doped structures and digital alloys have been investigated. In contrast to GaSb:Mn films, ...
The performance of a thermophotovoltaic (TPV) converter for solar energy is compared with that of direct solar energy conversion by silicon and germanium solar cells. The optical selectivity of an intermediate emitter is computed. Experimental results on selective emission, based on selectively emitting materials and on antireflection coatings on metals, are reported. For a TPV converter equipped with silicon solar cells, no selective emitter is found to yield better results than would be obtained by direct conversion. A TPV converter with germanium cells operating with a ThO/sub 2/-coated tungsten emitter, however, may achieve a conversion efficiency superior to that of direct solar energy conversion by either silicon or germanium solar cells.
Despite the rapid development of literature pertaining to fundamental (1-4) studies of oxidation catalysis, a general theory of heterogeneous selective oxidation catalysis explaining the selectivity behavior of different metal oxide systems has not yet been developed. Redox mechanisms have been widely invoked in the kinetic and mechanistic descriptions of selective oxidation reactions, suggesting a dynamic behavior of hydrocarbon and oxygen interactions with the catalyst surface. Nevertheless, most of the recent theoretical approaches of this subject matter (5-7) are essentially static in nature. Correlations are made with surface structure on the basis of crystallographic considerations with selectivity being related to the nature, number, bond-strength and nearness of oxygen atoms in the neighborhood of adsorption centers. The effect of the reaction medium on the configuration of the catalyst surface, ...
Educational data mining (EDM) is a new growing research area and the essence of data mining concepts are used in the educational field for the purpose of extracting useful information on the behaviors of students in the learning process. In this EDM, feature selection is to be made for the generation of subset of candidate variables. As the feature selection influences the predictive accuracy of any performance model, it is essential to study elaborately the effectiveness of student performance model in connection with feature selection techniques. In this connection, the present study is devoted not only to investigate the most relevant subset features with minimum cardinality for achieving high predictive performance by adopting various filtered feature selection techniques in data mining but also to evaluate the goodness of subsets with different cardinalities and the quality of six filtered feature ...
ObjectiveThe objective of this study was to identify patterns of brain activation elicited by erotic visual stimuli in patients treated with either Selective Serotonin Reuptake Inhibitors...Full Text Available
The objectives of this study were to select and initially characterize mutants of soybean (Glycine max L. Merr. cv Williams) with decreased ability to reduce nitrate. Selection involved...Full Text Available
Selective estrogen receptor modulators (SERMs) represent a class with a growing number of compounds that act as either estrogen receptor agonists or antagonists in a tissue-specific manner. This article...Full Text Available
Types of disorders in the earth's surface as a result of open pit mining operations are analyzed. Trends for recultivation of lands are defined. Formulas are presented for calculating the economic expediency of the selected direction of recultivation.
BackgroundUnderstanding the interactions between ion channels and blockers remains an important goal that has implications for delineating the basic mechanisms of ion channel function...Full Text Available
The objectives of this research are: (1) to assess selected formulation-relevant physical properties of several commercial Feverfew extracts, including flowability, hygroscopicity, compressibility and...Full Text Available
Direct identification of group B streptococci from a selective broth medium was performed with the Phadebact streptococcus test to determine the feasibility of this technique for early detection of...Full Text Available
We evaluated whether ejaculatory dysfunction induced with a selective α1A-blocker influenced orgasm. Fifteen healthy male volunteers took silodosin or a placebo in a randomized, double-blind...Full Text Available
Importance of the fieldThe cytochrome P450 (CYP) isoforms that are selectively induced following exposure to structurally-diverse chemicals often are the ones capable...Full Text Available
BackgroundScorpion venom contains insect and mammal selective toxins. We investigated the venom of the South Indian red scorpion, Mesobuthus tamulus for the purpose...Full Text Available
With the advent of dense maps of human genetic variation, it is now possible to detect positive natural selection across the human genome. Here we report an analysis of over 3 million polymorphisms...Full Text Available
BackgroundMicroarray data are often used for patient classification and gene selection. An appropriate tool for end users and biomedical researchers should combine user friendliness...Full Text Available
OBJECTIVE: To evaluate the commercial microparticle enzyme immunoassay (MEIA), Abbott IMx Select Chlamydia, for the detection of Chlamydia trachomatis in women and to compare its performance with endocervical...Full Text Available
We compared MRSA Select to mannitol-salt agar with 8 μg/ml cefoxitin for the detection of methicillin-resistant Staphylococcus aureus (MRSA) from 6,199 clinical...Full Text Available
Many pathogens colonize different anatomical sites, but the selective pressures contributing to survival in the diverse niches are poorly understood. Group A Streptococcus (GAS) is...Full Text Available
In this paper, we propose an antenna selection method in a wireless cognitive radio (CR) system, namely difference selection, whereby a single transmit antenna is selected at the secondary transmitter out of $M$ possible antennas such that the weighted difference between the channel gains of the data link and the interference link is maximized. We analyze mutual information and outage probability of the secondary transmission in a CR system with difference antenna selection, and propose a method of optimizing these performance metrics of the secondary data link subject to practical constraints on the peak secondary transmit power and the average interference power as seen by the primary receiver. The optimization is performed over two parameters: the peak secondary transmit power and the difference selection weight $\\delta\\in [0, 1]$. We show that, difference ...
Recombinant biotin-binding phages were affinity-selected from a random peptide library expressed on the surface of filamentous phage. Phage binding to biotinylated proteins was half-maximally inhibited...Full Text Available
OBJECTIVES: Although the tricyclic antidepressant amitriptyline is extensively used in the prophylactic treatment of chronic tension-type headache, only few studies have investigated the efficacy of...Full Text Available
Six patient assessment systems that have explicit decision rules for replicating team judgments on level of care patient placement were selected for analysis. The six were selected because of their...Full Text Available
Surface temperature is measured with an infrared thermometer. Measuring Surface Temperature. Nine sample points are selected with a site of uniform land ...
Selection of detailed-items for Periodic Safety Review on PWR radwaste management system, the main component could be faithfully clarified according to the purpose of establishment on each system and basic purpose. It is proper to select detailed-items those of radioactivities in the reactor coolant activity levels and the released volume of liquid and gaseous radioactive material on safety performance. It's also proper to select solid radwaste production quantities as detailed-item that it would be predict the next ten years trends after PSR.
2.1.1 Levels of preservation and packaging and the levels of packing to be applied selectively are defined in MIL-STD-2073-1 and are mandatory for use or ...
Current technical specifications of Wolsong Unit 2,3,4 was analyzed and improvement methods was suggested to develop Improved Standard Technical Specifications(ISTS) of PHWR. The selection criteria of PHWR limiting condition for operation(LCO) was established, then limiting conditions for operationl were selected. The number of current LCOs for Wolsong Units 2,3,4 is 109, and 46 LCOs(42%) were relocated by the selection criteria of PHWR LCO. 63 LCOs which met the selection criteria of PHWR LCO were recomposed to 59 LCOs.
Under different sintering temperatures(340 degrees C, 440 degrees C, 540 degrees C, 640 degrees C), four TiO2 particles were prepared. The crystal types of all four samples were found to possess anatase structures by XRD. It was obtained by N2 experimental adsorption at low temperature (77K) that their surface areas and average pore size were between 79 and 124 m2/g, 56.8 and 254.8 A respectively. The pore structure of TiO2 particles was characterized by scanning electron microscope (SEM). The tests of adsorption dynamics for FGD and the performance of SO2 removal were investigated in a fixed-bed system for different samples. The results show that SG540 sample which made at 540 degrees C sintering temperature had the most quality among the four samples. It can adsorb SO2 of 38.9 mg for one gram SG540 sample. Different operating conditions for SG540 such as adsorption temperature, SO2 concentration in flue gas and the superficial velocity of flue gas were investigated. TiO2 particles ...
This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period October--December 1997. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within six major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Separations and Materials Synthesis, Fluid Structure and Properties, Biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information. Activities conducted within the area of Hot Cell Operations included efforts to optimize the processing conditions ...
Batch interaction experiments were performed under aerobic conditions to characterize the adsorption behavior and valence speciation of CoEDTA complexes (equimolar at 10{sup -5} mol/L) in a series of Pliocene subsurface sediments containing various amounts of Fe and Mn oxides. The experiments were performed in 0.003 mol/L Ca(ClO{sub 4}){sub 2} with a solids concentration of 500 g/L at variable pH (4-9) and at the natural pH of the sediments (pH = 8.3). Three of these subaerial sediments (Ringold 1, 2, 3) contained significant quantities of extractable Fe and Mn, while the fourth (Ringold 4) was virtually devoid of sesquioxide precipates. Microscopic and mineralogic analyses of the most heavily encrusted material (Ringold 2) showed that the oxides existed as intergrain cements and contained crystalline goethite and rancieite/todorokite. Adsorption on a synthetic analog sorbent (0.6 mass% ferrihydrite-coated sand) over a range in pH showed that, while both Co(II) ...
This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the ...
The objective of this project is to develop a pellet formulation which is capable of achieving low sulfur partial pressures and a high capacity for sulfur, loaded from a hot fuel gas and which is readily regenerable. Furthermore the pellet must be strong for potential use in a fluidized bed and regenerable over many cycles of loading and regeneration. Regeneration should be in air or oxygen-depleted air to produce a high-concentration sulfur dioxide. Fixed-bed tests were conducted with several formulations of manganese sesquioxide and titania, and alumina They were subject to a simplified fuel gas of the oxygen-blown Shell type spiked with a 30,000ppmv concentration of H{sub 2}S. Pellet crush strengths for 4 and 2mm diameter pellets was typically 12 lbs per pellet and 4 lbs per pellet, respectively. For the most favorable of the formulations tested and under the criteria of break-through at less than 100ppmv H2S and loading temperatures of 500{degrees}C and an empty-bed space velocity ...
Three reactive materials were evaluated at laboratory scale to identify the optimum treatment reagent for use in a Permeable Reactive Barrier Treatment System at Rocky Flats Environmental Technology Site (RFETS). The contaminants of concern (COCS) are uranium, TCE, PCE, carbon tetrachloride, americium, and vinyl chloride. The three reactive media evaluated included high carbon steel iron filings, an iron-silica alloy in the form of a foam aggregate, and a peculiar humic acid based sorbent (Humasorb from Arctech) mixed with sand. Each material was tested in the laboratory at column scale using simulated site water. All three materials showed promise for the 903 Mound Site however, the iron filings were determined to be the least expensive media. In order to validate the laboratory results, the iron filings were further tested at a pilot scale (field columns) using actual site water. Pilot test results were similar to laboratory results; consequently, the iron ...
Sorption studies of cesium, strontium, and cobalt (Cs, Sr, and Co) on bentonite under various experimental conditions, such as contact time, pH, sorbent and sorbate concentration, and temperature, have been performed. The sorption data for all these metals have been interpreted in terms of Freundlich, Langmuir, and Dubinin-Radushkevich equations. Thermodynamics parameters, such as heat of sorption {Delta}H{degrees}, free energy change {Delta}G{degrees}, and entropy change {Delta}S{degrees}, for the sorption of these metals on bentonite have been calculated. The value of {Delta}H{degrees} shows that the sorption of Cs was exothermic, while the sorption of Sr and Co on bentonite were endothermic in nature. The value of {Delta}G{degrees} for their sorption was negative, showing the spontaneity of the process. The maximum loading capacity of Cs, Sr, and Co were 75.5, 22, and 27.5 meq, respectively, for 100 g of bentonite. The mean free energy E of Cs, Sr, and Co ...
Immobilization of a model liquid organic pollutant, i.e. the 2-chloroaniline (2-CA), into a cement matrix using organoclays as pre-sorbent agents was investigated. Five cement-clay pastes were prepared with different nominal water-to-cement ratios (w/c=0.40, 0.25 and 0.15 wt/wt) and various amounts of waste (waste-to-cement o/c=0.20, 0.60 and 1.00 wt/wt); for comparison, a neat cement paste was also prepared. Dynamic leach tests were performed on solidified monoliths in order to assess the successful immobilization of the 2-CA. In monoliths at constant w/c ratio (0.40) the total amount of pollutant released increases with its initial content, and ranges from 15 to 35% with respect to it. By lowering w/c from 0.40 to 0.15 at constant o/c, the performances improved (<25% released). The microstructure of the hardened cement-clay pastes was characterized by quantitative X-ray diffraction (QXRD) and electronic microscopy (SEM-EDS) techniques; hydration degree was ...
A relational database capable of storing and manipulating the large volumes of data on air toxic metals has been developed for the Center for Air Toxic Metals at the Energy and Environmental Research Center (EERC) of the University of North Dakota. The database provides information to researchers, managers, and operations personnel to aid in their decision making and long-term planning of issues related to air toxic metals. A personal computer-based graphical user interface is used to access the data located on a UNIX workstation at the EERC. With security codes and software issued by the EERC and an Internet service provider in place, the database can be accessed externally through the Internet. Currently the database contains over 3000 analytical measurements from nine full-scale systems and several bench-scale operations. Data are available on gas, solid, and liquid stream samples as well as relevant engineering parameters, including process data. Data will be input on a continual ...
The article explains the method of selecting the optimum energy for correcting the energy selectivity of tomographic projection and the optimum length of the crystals corresponding to it when the dual energy method in computerized tomography is used. Results of numerical calculations for actual materials and count results are presented.
In this paper, a new design methodology for determining the size, location, type and number of capacitors to be placed on a radial distribution system is presented. The objective is to minimize the peak power losses and the energy losses in the distribution system considering the capacitor cost. A sensitivity analysis based method is used to select the candidate locations for the capacitors. A new optimization method using a Genetic Algorithm is proposed to determine the optimal selection of capacitors. Test results have been presented along with the discussion of the algorithm.
Investigation of selective emitter solar cells has been undertaken using both device fabrication and accurate two-dimensional simulation program. Our results show that selective emitter solar cells exhibit a relatively low fill factor because of minority carriers crowding at the lateral junction. It is also found that carrier recombination in the space-charge region of the lateral junction limits open-circuit voltage improvements
Isotopically selective IR multiphoton dissociation of molecules (SF_6, CF_3I) in a pulsed gas-dynamic flow interacting with a solid surface was studied for the first time. A noticeable (severalfold) increase in the yield of products (compared to excitation of molecules in an unperturbed flow) without a substantial decrease in the selectivity of the process was observed. Possible reasons for the effect are discussed. (laser applications and other topics in quantum electronics)
Supplement B to the Terra Nova Development Application provides a description of the floating production storage and offloading (FPSO) vessel system selected for the development, a summary of the reasons for selecting the system, and the impact of this selection on the Development Plan, the Benefits Plan, the Environmental Impact Statement and the Socio-Economic Impact Statement. There is also a description of the contractor alliance approach to be used in the Terra Nova Development. Refs., tabs., figs.
Coatings and sensors having both steric and chemical selectivity. Controlled porosity provides the steric selectivity, whereas chemically tailored film properties, using controlled composition or modification by coupling agents, chemical species replacement, or chemical species within pores, provide the chemical selectivity. Single or multiple layers may be provided.
Nanosized particles are important because of their unique properties, different from the bulk, which leads to their enhanced catalytic, photocatalytic and electronic properties. This work has dealt with three different nanoparticle systems in the context of three different aspects of nanoparticle properties: (a) photocatalytis (TiO2/metal) system, (b) luminescence (CdSe) (c) alloying (Pt-Ag and Pd-Ag). The initial photocatalytic enhancement obtained by adding noble metal on semiconductor nanoparticles, degrades as fast as in 15 minutes and questions their long-term performance. XANES measurements on such irradiated systems like TiO2/Au, TiO2/Pt, TiO2/Ir indicates a positive oxidation state of these noble metals which renders them as recombination centers for photo-excited electrons and explains the decreased photocurrent. The oxidation is caused by holes. The EXAFS results also indicate a change of the interfacial structure under the effect of UV-irradiation, thus ...
We report the influence of a small quantity of Cl[sub 2], which enhanced the selectivity of silicon-selective epitaxial growth (Si-SEG) in UHV-CVD using Si[sub 2]H[sub 6], on both the epitaxial growth rate and the B-doping properties for each Si and Si[sub 1-x]Ge[sub x] film. The small quantity of Cl[sub 2] inhibited the Si, Ge and B incorporation, while the selectivity was enhanced. However, it was found, in the case of Si[sub 1-x]Ge[sub x]-SEG using Cl[sub 2], that the reduction ratio of both the growth rate and the B incorporation were smaller than those of Si-SEG with the selectivity still more enhanced. (orig.)
Selective formation of ZnO nanodots was accomplished by metalorganic chemical vapor deposition on nanopatterned SiO_2/Si substrates. Self-organized ZnO nanodots were selectively formed in nanopatterned lines of Si created by etching of SiO_2 with focused ion beam (FIB), whereas any nanodots were hardly observed on the SiO_2 surface in the vicinity of the FIB-sputtered Si areas. The mechanism of the selective formation of ZnO nanodots on FIB-nanopatterned lines is mainly attributed to the effective migration of Zn adatoms diffusing on the SiO_2 surface into the Si lines followed by the nucleation at surface atomic steps and kinks created by Ga"+ ion sputtering. Cathodoluminescence measurements confirmed that the emission originated from the selectively grown ZnO nanodots.
Model selection aims to determine which theoretical models are most plausible given some data, without necessarily asking about the preferred values of the model parameters. A common model selection question is to ask when new data require introduction of an additional parameter, describing a newly-discovered physical effect. We review several model selection statistics, and then focus on use of the Bayesian evidence, which implements the usual Bayesian analysis framework at the level of models rather than parameters. We describe our CosmoNest code, which is the first computationally-efficient implementation of Bayesian model selection in a cosmological context. We apply it to recent WMAP satellite data, examining the need for a perturbation spectral index differing from the scale-invariant (Harrison-Zel'dovich) case.
Feature selection refers to the problem of selecting relevant features which produce the most predictive outcome. In particular, feature selection task is involved in datasets containing huge number of features. Rough set theory has been one of the most successful methods used for feature selection. However, this method is still not able to find optimal subsets. This paper proposes a new feature selection method based on Rough set theory hybrid with Bee Colony Optimization (BCO) in an attempt to combat this. This proposed work is applied in the medical domain to find the minimal reducts and experimentally compared with the Quick Reduct, Entropy Based Reduct, and other hybrid Rough Set methods such as Genetic Algorithm (GA), Ant Colony Optimization (ACO) and Particle Swarm Optimization (PSO).
We consider relay selection technique in a cooperative cellular network where user terminals act as mobile relays to help the communications between base station (BS) and mobile station (MS). A novel relay selection scheme, called Joint Uplink and Downlink Relay Selection (JUDRS), is proposed in this paper. Specifically, we generalize JUDRS in two key aspects: (i) relay is selected jointly for uplink and downlink, so that the relay selection overhead can be reduced, and (ii) we consider to minimize the weighted total energy consumption of MS, relay and BS by taking into account channel quality and traffic load condition of uplink and downlink. Information theoretic analysis of the diversity-multiplexing tradeoff demonstrates that the proposed scheme achieves full spatial diversity in the quantity of cooperating terminals in this network. And numerical results are provided to further ...
The problem of model selection arises in a number of contexts, such as subset selection in linear regression, estimation of structures in graphical models, and signal denoising. This paper generalizes the notion of "incoherence" in the existing literature on model selection and introduces two fundamental measures of coherence---termed as the worst-case coherence and the average coherence---among the columns of a design matrix. It utilizes these two measures of coherence to provide an in-depth analysis of two variants of a simple one-step thresholding (OST) algorithm for model selection and proves that OST is feasible for model selection as long as the design matrix obeys an easily verifiable property. One of the key insights offered by the ensuing analysis in this regard is that if the design matrix has reasonably small worst-case and average coherence then OST performs ...
Long-term divergent selection for low or high body weight from the same founder population has generated two extremely divergent lines of chickens, the high- (HWS) and low-weight (LWS) selected lines. At selection age (56?days), the lines differ by more than nine times in body weight. The HWS line chickens are compulsive feeders, whereas in the LWS line, some individuals are anorexic and others have very low appetite. Previous studies have implicated the central nervous system and particularly the hypothalamus in these behavioural differences. Here, we compared the mRNA expression in hypothalamus tissue from chickens on day?4 post-hatch using oligonucleotide arrays and found that the divergent selection had resulted in minor but multiple expression differences. Differentially expressed gen...
Object: To smoothly control automatic water supply for realizing stable operation of a nuclear reactor by providing a flow rate limiting signal selection circuit and a preferential circuit in a water supply control device for a nuclear reactor wherein the speed of a recirculation pump may be changed in two-steps. Structure: Opening angle signals for a water supply regulating valve are controlled by a nuclear reactor water level signal, a vapor flow rate signal and a supplied water flow rate signal through an adder and an adjuster in response to a predetermined water level setting signal. When the water in the reactor is maintained at a predetermined level, a selection circuit receives a water pump condition signal for selecting one of the signals from a supplied water rate limiting signal generator generating signals for indicating whether one or two water supply pumps are operated. A low value preferential circuit passes ...
The authors present the emitter efficiency results for the thin film 25 percent Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) selective emitter from 1000 to 1700 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2 less than lambda less than 3.2 microns) and used to calculate the radiative efficiency. The radiative efficiency and power density of rare earth doped selective emitters are strongly dependent on temperature and experimental results indicate an optimum temperature (1650 K for Ho YAG) for thermophotovoltaic (TPV) applications.
Single and selective pole tripping schemes may be used to maintain a desired level of system integrity while minimizing transmission line expenditures. In general, these schemes will be most effective on those portions of the system where relatively few interconnections exist. While selective pole tripping may superficially appear to provide more margin than single pole schemes in the preservation of system stability, it seems unlikely that in those actual applications where single pole tripping is warranted that selective pole tripping will provide any significant advantages.
For the selective extraction of radionuclides from nitrate media, the extractabilities of organo-poly-phosphine poly-oxides were examined in the form of impregnated resins. It was found that the extractability of 1,1,3,5,5-pentaphenyl-1,3,5-tri-phospha-pentane trioxide (PPTPT) for U(VI) is quite unusual with very high values at both low and high concentrations of nitric acid, which is not observed for other types of extractants. Thus, this extractant might be promising for the selective extraction of U(VI) in very high concentrations of HNO3. (authors)
High-resolution spectroscopy of 13 bright red giants and Ba stars shows selective enhancement of Ba in three of them, HD 65699 (Ba 2), ..cap alpha..TrA (K4 III), and epsilonPeg (K2 Ib). Infrared spectra available for HD 65699 show that Sr is enhanced, too. This selective enhancement is discussed in terms of a modified s-process which converts some of the pre-existing r- and s-process matter into the magic nuclei /sup 88/Sr and /sup 138/Ba.
The transverse modes of a submillimetre laser cavity that contains waveguides and open parts were studied theoretically and experimentally with the purpose of finding methods for mode selection. Two methods based on the filtering of the Fourier spectra of the waveguide modes and the use of their interference were substantiated numerically and realised in experiment. Special attention was paid to the mode selection in tunable lasers. Scaling laws allowing one to use the obtained results in a wide range of the cavity parameters and wavelengths are presented. (laser applications and other topics in quantum electronics)
A method for analyzing the experimental results of coal liquefaction reactions which is applicable to a number of aspects of coal liquefaction research and process control, including rapid selectivity and performance screening for catalysts; correlation of laboratory results with process parameters; and optimization of product yield with plant process conditions is described here. Ternary diagrams of product/by-product distributions for the coal liquefaction using Co/Mo catalysts combined with a hyperbolic relationship for the conversion of various hydrocarbon fractions can be used for catalyst screening. A hydrogen consumption diagram used to provide a more significant selectivity test than the hyperbolic correlation is also included. (BLM)
Oxidation of propylene with oxygen, air and a mixture of nitrogen?oxygen in a barrier discharge is investigated. The selectivity towards formation of propylene oxide in pure oxygen is shown to be as high as 45 wt% and the propylene conversion ratio is found to be 12.9 wt%. In the oxidation with air, the propylene oxide selectivity is 23 wt%, while the conversion is 7.5 wt%. The values of propylene conversion and selectivity towards formation of propylene oxide in a barrier discharge are consistent with those obtained by the thermocatalytic methods for production of propylene oxide.
In this paper, it is suggested that the selection method of optimal parameter of power system stabilizer (PSS) with robustness in low frequency oscillation for power system using real variable elitism genetic algorithm (RVEGA). The optimal parameters were selected in the case of power system stabilizer with one lead compensator, and two lead compensator. Also, the frequency responses characteristics of PSS, the system eigenvalues criterion and the dynamic characteristics were considered in the normal load and the heavy load, which proved usefulness of RVEGA compare with Yu's compensator design theory. (author). 20 refs., 15 figs., 8 tabs.
A temperature gradient across a thick ({ge}.1mm) film selective emitter will produce a significant reduction in the spectral emittance from the no temperature gradient case. Thick film selective emitters of rare earth doped host materials such as yttrium-aluminum-garnet (YAG) are examples where temperature gradient effects are important. In this paper a model is developed for the spectral emittance assuming a linear temperature gradient across the film. Results of the model indicate that temperature gradients will result in reductions the order of 20{percent} or more in the spectral emittance. {copyright} {ital 1997 American Institute of Physics.}
This paper presents an analysis of the performance of a selective emitter using small particles of rare earth compounds stable at high temperatures in a low emittance inert gas stream. An expression for the spectral emissive power excluding radiation scattering was derived to include the radiation in the emission band, produced by electronic transitions of the rare earth ion, and the continuum radiation outside the emission band produced by the rare earth host. Preliminary results suggest that a selective emitter based on suspended rare earth oxide particles will have high efficiency and merits further experimental investigation. {copyright} {ital 1996 American Institute of Physics.}
Sep 1, 2011 ... Recent wildfires in interior Alaska have left substantial volumes of burned timber, potentially usable for biomass energy. Motivated,in part, by ...
Background. To determine total upper limb function following selective neck dissection over a mean follow-up of 1.6 years. Methods. A retrospective questionnaire study in a tertiary head and neck surgical unit. One hundred forty-eight patients who underwent selective neck dissection for head and neck cancer from January 2000 to December 2005 were invited to participate. The main outcome measure was ipsilateral upper limb dysfunction as measured by the Disability of Arm, Shoulder and Hand (DASH) questionnaire. Results. Sixty-five patients responded to the invitation to join the study from 148 invited. Despite accessory nerve conserving surgery for all the selective neck dissections studied, 23% reported no upper limb dysfunction, 54% reported mild upper limb dysfunction, 15% reported modera...
Ultraconserved elements (UCEs) are sequences that are identical between reference genomes of distantly related species. As they are under negative selection and enriched near or in specific classes...Full Text Available
The transformation and the accommodation of National Power System (SEN) units to a new management system, own to a decentralized economy and having financial support from both native capital and foreign capital, in uncertain proportion at the moment and being in a continuous adjustment determined by the reasons and the motivations first of all political, generated conceptual changes in the so-called modern management theory. The accommodation of this theory to the concrete situation from SEN units imposed the concept of negative selection. It is a concept which represents author's desire to be created as an original contribution to the contemporary management theory. Unlike the selection at the hiring (or positive selection), the negative selection is achieved on personal already employed, in the conditions of activities of a decreased number of personnel and also of a redistribution of personnel on the ...
Selection of the appropriate radiation quality is an important aspect of optimisation for every clinical imaging task in radiology, since it affects both image quality and patient dose. Spreadsheet...Full Text Available
We present results on searches for exotic particles (relativistic magnetic monopoles and WIMPs) and for UHE neutrinos, obtained with the Baikal neutrino telescope NT200.
Objectives: To evaluate the training of pharmacists in Accra, Ghana, in the syndromic management of STIs. Methods: We randomly selected 50 pharmacy outlets that had...Full Text Available
A specific radiochemical procedure for indium determination in semiconductor-grade silicon, using an inorganic ion exchanger (cerium oxalate) is proposed.
Deltombe T, Gustin T. Selective tibial neurotomy in the treatment of spastic equinovarus foot in hemiplegic patients: a 2-year longitudinal follow-up of 30 cases. Objective To assess the long-term efficacy of selective tibial neurotomy in the treatment of spastic equinovarus foot in hemiplegic patients. Design Intervention study (before-after trial) with an observational design and 2-year follow-up. Setting Spasticity group in a university hospital. Participants Hemiplegic patients (N=30) with spastic equinovarus foot. Intervention A selective neurotomy was performed at the level of the motor nerve branches of the tibial nerve. Main Outcome Measures Spasticity (Ashworth scale), muscle strength (Medical Research Council scale), passive ankle dorsiflexion, gait parameters (6 min walking test...
This paper proposes a new approach based on missing value pattern discovery for classifying incomplete data. This approach is particularly designed for classification of datasets with a small...Full Text Available
... as the difference between date of birth and date of ... Final model selections were based on the ... approval by the Naval Submarine Medical Research ...
Synthetic polymers and nanomaterials display selective phenotypic effects in cells and in the body that affect signal transduction mechanisms involved in inflammation, differentiation, proliferation,...Full Text Available
... And those who study cognition select problems (eg, tower of Hanoi, missionaries and cannibals, logic theorems) with minimal perceptual and motor ...
Significant research has been carried out in the recent years for generating systems exhibiting intelligence for realizing optimized routing in networks. In this paper, a grade based twolevel based node selection method along with Particle Swarm Optimization (PSO) technique is proposed. It assumes that the nodes are intelligent and there exist a knowledge base about the environment in their local memory. There are two levels for approaching the effective route selection process through grading. At the first level, grade based selection is applied and at the second level, the optimum path is explored using PSO. The simulation has been carried out on different topological structures and it is observed that a graded network produces a significant reduction in number of iteration to arrive at the optimal path selection.
Several years ago, the AGARD Structures and Materials Panel selected ... flow separation appears to have occurred during the tests, and the angles of attack ...
NEWTON's first law prohibits the coupling of free tachyons to ordinary matter, if it is interpreted as selection rule interdicting emission without change of the rest-mass of the emitting system.
The tremendous growth of wireless technologies has introduced the potential of continuous service adaptation to the users' needs by giving them the ability to be able to select and access the proper network based on different criteria. Moreover, next generation wireless networks have been designed to provide support for multimedia services, with different traffic characteristics and different Quality of Service (QoS) guarantees. However, the expansion of Wireless Local Area Networks (WLANs) and Worldwide Interoperability for Microwave Access (WiMAX) networks poses new research era in the decision of the access network selection. In this paper, the existing access network selection schemes are classified into three categories: the network-centric, the user-centric and the collaborative sche...
Jul 7, 2008 ... HOUSTON -- Following a detailed, integrated assessment, NASA selected ... in the center that provides a 360-degree view around the station. ...
The KDP crystal was 10 cm long and cut such that the c-axis was 50.3* to the normal of its input face. We selected for study idler and signal beams ...
BackgroundWhereas there is increasing evidence that loss of expression and/or function of the thyroid hormone receptors (TRs) could result in a selective advantage for tumor development,...Full Text Available
... the area covered by the point-count grid, stopping approximately every 100 m, stepping away from the vehicle, and scanning with binoculars for mountain plovers. Once ... ...
The purpose of this report is to provide management with performance data on key performance indicators selected from the FFTF Early Warning System performance indicators.
... Using a weighted linear regression on randomly selected coincident SSM/I-buoy pairs from each of the climate m codes, it was possible to produce ...
... This is the case for the 82nd Airborne Division ready brigade force (DRB) and the Military Airlift Command (MAC) strategic airlift system operating ...
By using the paired comparison methodology, it was possible to establish evaluative priorities, providing criterion weights which reflected the thoughts and feelings of an advisory committee consisting of experts in the task selection process. For the U.S. Army Infantry School, the weights can be used to stress higher weighted criterion results in the task selection process. By extending the size and diversity of the advisory committee, the use of paired comparison methodology can provide an effective, reliable procedure for (1) constructing evaluative criterion weights for the task selection process and in other areas which have multiple criteria used for evaluative purposes and (2) incorporating into an evaluative design the valuable contributions of various experts and interest groups. (Author/BW)
Direct plating, selective enrichment, and cold enrichment followed by secondary selective enrichment procedures were compared for detecting and enumerating Listeria monocytogenes in chopped cabbage stored at 5 degrees C for up to 64 days. Addition of Fe3+ to solid media enhanced detection of the organism. Cold enrichment (5 degrees C) in nutrient broth and brain heart infusion broth followed by secondary enrichment (48 h, 30 degrees C) in Trypticase soy-yeast extract-antibiotic broth and thiocyanate-nalidixic acid broth and plating on selective agar media (Doyle and Schoeni selective enrichment agar [minus acriflavin hydrochloride, supplemented with 5 micrograms of Fe3+/ml] and McBride Listeria agar) resulted in the detection of highest populations. PMID:3111369
... spontaneous radiation of amplifiers within a relatively w~de range of ... pulse widths are 20-30ns, while amplified spontaneous radiation pulse ...
[Originating_Center='Centro Nacional Patagonico-Laboratorio de Mamiferos Marinos ']. Refine by Category. Please select a field, Projects, Data Centers ...
The goal of this investigation is to research possible methodologies into automating the design of, specifically, nuclear power facilities; however, it is relevant to all thermal power systems. The strategy of this research has been to concentrate on individual areas of the thermal design process, investigate procedures performed, develop methodology to emulate that behavior, and prototype it in the form of a computer program. The design process has been generalized as follows: problem definition, design definition, component selection procedure, optimization and engineering analysis, testing and final design with the problem definition defining constraints that will be applied to the selection procedure as well as design definition. The result of this research is a prototype computer program applying an original procedure for the selection of the best set of real components that would be used in constructing a system with ...
This paper examines why ship shaped floating production storage and offloading (FPSO) systems have been selected for the first two developments on Foinaven and Schiehallion fields in West of Shetland operated by BP Exploration. An overview of the concepts considered for the deepwater harsh environment is made against the business objectives and reservoir conditions which are the primary drivers behind development concept selection. Discussion of technical issues for a range of concepts are held on schedule, construction, installation, safety, flexibility to production throughput, capital and operating costs.
...The system recognises the name and confirms it before it starts to dial. To stop the number being dialled say 'cancel'. If ...of the conference : Press the Recall 'R' button and listen for holding dial tone. Select extension or outside number of the person to ...who is going to join the conference Press Recall 'R' to receive dial tone and select '*' and '4'. The call is ...line is faulty and should be reported to the switchboard operators by dialling '0' and giving full details of the fault, the extension ...
Details are given of the Sasol operation in South Africa. Flow sheets are provided for Sasol 1 and Sasol 2 and 3. The Sasol 1 plant produces waxes, liquid fuels, pipeline gas and chemicals; the Sasol 2 and 3 plants primarily produce ethylene, gasoline and diesel fuel. The versatility of the process is emphasized. The product selectivities of the fixed bed and Synthol reactors are shown and the properties of the products are compared. The influence of the catalyst on selectivity is examined.
Synthesis of the azido substituted non-steroidal anti-inflammatory drug 2-(2,6-dichloroanilino)phenylacetic acid and isotope labeling of this compound have been performed and are described. Initial evaluation of the binding ability and photoreactivity indicates that this compound has potential for photoaffinity labeling as well as enzyme selectivity studies. (author).
The sunlight-induced photocatalytic oxidation of aqueous benzene on TiO(2)-supported gold nanoparticles was considerably improved when the reaction was conducted under a CO(2) atmosphere. 13% yield and 89% selectivity of phenol was obtained on P25-supported gold nanoparticles under 230 kPa of CO(2). PMID:21952312
This paper shows some considerations about the cost of wood, steel and cement support pillars in rural power distribution systems. The life span, mechanical properties, cost estimation and general durability of each type of pillar was evaluated, aiming a better selection of the desired one. 6 figs., 8 tabs., 4 refs.
An amorphous mesoporous titania-silica aerogel (20 wt%TiO{sub 2} - 80 wt% SiO{sub 2}) and tert.-butylhydroperoxide (TBHP) have been used for the epoxidation of various allylic alcohols. Allylic alcohols possessing an internal double bond were more reactive than those with a terminal C=C bond. Epoxide selectivities could be improved by addition of (basic) zeolite 4 A and NaHCO{sub 3} to the reaction mixture. (orig.)
A new commercial cutting tool software package replaced an internally created legacy system. This report describes the issues that surfaced during the migration and installation of the commercial package and the solutions employed. The primary issues discussed are restructuring the data between two drastically different database schemas and the creation of individual component graphics.
The advantages of radiofrequency and microwaves, such as volumetric heating, rapid and selective heating, compactness of equipment and ease of operation, offer sound economic alternative heating techniques. This article discusses dielectric loss, its quantification, and how it is put to effective use, including the use of applicators. Brief recommendations are presented for whether to select radio frequency or microwaves for a particular application. Uses of radiofrequency and microwaves in the industrial, domestic and medical sectors are described.
Sterol regulatory element-binding protein (SREBP)-1 is a key transcription factor for the regulation of lipogenic enzyme genes in the liver. Polyunsaturated fatty acids (PUFA) selectively suppress hepatic...Full Text Available
Recent literature indicates that torsion of the left ventricle (LV) is a promising predictor for response to cardiac resynchronisation therapy (CRT). Among patients with severe heart failure, 45 to 75% of patients show rigid body rotation, where the base and apex rotate in the same direction, instead of normal, opposite rotation. The occurrence of this phenomenon seems to be a good indicator for response to CRT. From this review, it can be concluded that LV torsion might be a welcome addition to current selection criteria.
The report presents selected highlights of how research has contributed to the regulatory effort. It explains the research role of the NRC and nuclear safety research contributions in the areas of: pressure vessel integrity, piping, small- and large-break loss-of-coolant accidents, hydrogen and containment, source term analysis, seismic hazards and high-level waste management. The report also provides a summary of current and future research directions in support of regulation.
Certain transition metal chalcogenides are promising materials for use as cathodes in nonaqueous lithium batteries involving the intercalation into these layered compounds. The electrochemical behavior of the chalcogenides depends on various properties such as structure, stoichiometry, electrical conductivity, crystal morphology, etc. The influence of these properties and of the ultimate practical application of the battery on the selection of cathode material is discussed. Battery performance of selected cathode materials is discussed and life limitations due to the limited cycle life of lithium anodes are outlined. 15 refs.
The effect of the non-selective, 1-aminoindan-1,5-dicarboxylic acid (AIDA), and selective (3,4-dihydro-2H-pyrano[2,3-b]quinolin-7-yl)-(cis-4- methoxycyclohexyl) methanone (JNJ16259685),...Full Text Available
Marshall Hall was selected by the US Army Corps of Engineers to participate in the Energy Efficiency Analysis Program. The objective of this program is to assist military installations in identifying energy usage and cost saving projects at their facilities and possibly provide funding for projects. Entech Engineering, Inc. was selected to perform this study.
The irreducible representations associated with states of dipole symmetry have been calculated for the space groups O/sub h//sup 3/, the space group with the correct symmetry for A-15 phase compounds. Also assembled are the character tables of the O/sub h/3 group. Thus all thedirect interband dipole-transition selection rules for A-15 compounds can easily be determined.
Qualifying corrosion inhibitors for use in high velocity multiphase flowlines in arctic or subsea environments is discussed. The tests include high velocity flow loop corrosion tests, pumpability through 0.125 (0.318 cm) inch capillary at low temperatures, compatibility with Nylon 11, emulsion tendency testing, and partitioning characteristics. Laboratory and field data show the importance for using the above criteria for inhibitor selection.
This report deals with the selection of a data communication system for a remote metering system. It covers the following three types of systems: fiber optic, telephone line, and radio packet. It provides a methodology for selecting a communication system for a given remote metering system and a method for comparing costs.
The oxidative dehydrogenation (ODH) of light alkanes is an alternative way for the production of olefins. A wide variety of catalytic systems has been investigated. Vanadium oxide based catalysts were described in the literature as effective catalysts for the ODH of propane. The catalytic activity and selectivity depend on the kind of support material, the kind of dopants and the formation of complex metal oxide phases. In recent papers it was claimed that both orthovanadate and/or pyrovanadate species are selective for the ODH of propane. Niobia based materials were investigated as catalysts for acidic and selective oxidation type reactions. In the ODH of propane niobia exhibited a high selectivity to propene but the conversion of propane was low. V{sub 2}O{sub 5}-Nb{sub 2}O{sub 5} catalysts proved to be catalytically active and selective and showed no formation of oxygenates. In ...
A process is described for the selective oxidation of ammonia to nitric oxide in about 90% or greater yield with a minimum of nitrogen or dinitrogen oxide (N/sub 2/O) as by-products, comprising: (1) contacting gaseous ammonia in an oxygen containing gas optionally with an inert gaseous diluent with a mixed metal perovskite catalyst of the general formula: ABO/sub 3/, wherein: A is selected from the alkali, alkaline earth, lanthanide, or actinide metals or a mixture of these metals having a relatively large ionic, radius, and B is selected from an element or a combination of elements selected from Groups IB, IVB, VB, VIB, VIIB, or VIII of the Periodic Table, wherein the perovskite phase of the catalyst has an equilibrium partial pressure of oxygen at 1000/sup 0/C of greater than about 10/sup -15/ bar; and (2) heating the reactants of step (1) at greater than about 500/sup 0/C under conditions of 10 to ...
A process is described for the selective oxidation of ammonia to nitric oxide in about 90% or greater yield with a minimum of nitrogen or dinitrogen oxide (N/sub 2/O) as by-products, comprising: (1) contacting gaseous ammonia in an oxygen containing gas optionally with an inert gaseous diluent with a mixed metal perovskite catalyst of the general formula: ABO/sub 3/, wherein: A is selected from the alkali, alkaline earth, lanthanide, or actinide metals or a mixture of these metals having a relatively large ionic, radius, and B is selected from an element or a combination of elements selected from Groups IB, IVB, VB, VIB, VIIB, or VIII of the Periodic Table, wherein the perovskite phase of the catalyst has an equilibrium partial pressure of oxygen at 1000"0C of greater than about 10/sup -15/ bar; and (2) heating the reactants of step (1) at greater than about 500"0C under conditions of 10 to 100,000 ...
New rare earth oxide emitters show greater efficiency than previous emitters. As a result, based on a simple model the efficiency of these emitters was calculated. Results indicate that the emission band of the selective emitter must be at relatively low energy (less than or equal to .52 eV) to obtain maximum efficiency at moderate emitter temperatures (less than or equal to 1500 K). Thus low bandgap energy PV materials are required to obtain an efficient thermophotovoltaic (TPV) system. Of the 4 specific rare earths (Nd, Ho, Er, Yb) studied Ho has the largest efficiency at moderate temperatures (72 percent at 1500 K). A comparison was made between a selective emitter TPV system and a TPV system that uses a thermal emitter plus a band pass filter to make the thermal emitter behave like a selective emitter. Results of the comparison indicate that only for very optimistic filter and thermal emitter properties will the filter ...
Because hydrogenation of coal to liquid products (oils) is accompanied by distributions of complex by-product mixtures (IOM, preasphaltenes, asphaltenes and gases) which change as a function of reaction variables (time, temperature and pressure) and reactor configuration, the determination of selectivity relationships for coal liquefaction catalysts has been a difficult and time-consuming task involving numerous experiments to adequately describe catalyst performance over a range of conditions. This paper describes a method for analyzing the experimental results of coal liquefaction reactions which may be applied to a number of aspects of coal liquefaction research and process control, including: rapid selectivity and performance screening for catalysts; correlation of laboratory results with process parameters; and optimization of product yield for plant process conditions. Catalyst selectivity and performance screening ...
Macronutrient self-selection and responses to dietary protein dilution were investigated in Senegalese sole, a flatfish species of interest for Mediterranean aquaculture. Eight groups of six sole were distributed among 75-l tanks and allowed to feed on three experimental diets composed of pure macronutrients: PC (75% crude protein and 25% carbohydrate), PF (75% crude protein and 25% crude fat) and PFC (10% crude protein, 45% crude fat and 45% carbohydrate). Choosing from the above diets, the sole selected a diet containing 68.0% crude protein, 15.7% crude fat and 16.3% carbohydrate. When the PF diet was diluted 50% with cellulose, the fish increased their feed intake to sustain the energy intake (5.0?kJ/kg BW/day). Their selection of fat remained unchanged, while carbohydrate selection sig...
We construct a sample of low-redshift Ly-alpha emission-line selected sources from GALEX grism spectroscopy of nine deep fields to study the role of Ly-alpha emission in galaxy populations with cosmic time. Our final sample consists of 122 (142) sources selected in the redshift interval z=0.195-0.44 (z=0.65-1.25) from the FUV (NUV) channel. We classify the Ly-alpha sources as AGNs if high-ionization emission lines are present in their UV spectra and as galaxies otherwise. These classifications are broadly supported by comparisons with X-ray and optical spectroscopic observations. We classify additional sources as AGNs using line widths for our Ly-alpha emitter (LAE) analysis. Defining the GALEX LAE sample in the same way as high-redshift LAE samples, we show that LAEs constitute only about 5% of NUV-continuum selected galaxies at z~0.3. We also show that they are less common at z~0.3 than they are at z~3. We find that the ...
Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1200K. Both selective emitter and filter system TPV systems are feasible. However, requirements on the filter system are severe in order to attain high efficiency. A thin-film of a rare-earth oxide is one method for producing an efficient, rugged selective emitter. An efficiency of 0.14 and power density of 9.2 W/KG at 1200K is calculated for a hypothetical thin-film neodymia (Nd2O3) selective emitter TPV system that uses radioisotope decay as the thermal energy source.
We analyze the average of weak values over statistical ensembles of pre- and post-selected states. The protocol of weak values, proposed by Aharonov et al. [Phys. Rev. Lett. 60 (1988) 1351], is the result of a weak measurement conditional on the outcome of a subsequent strong (projective) measurement. Weak values can be beyond the range of eigenvalues of the measured observable and, in general, can be complex numbers. We show that averaging over ensembles of pre- and post-selected states reduces the weak value within the range of eigenvalues of Formula Not Shown . We further show that the averaged result expressed in terms of pre- and post-selected density matrices, allows us to include the effect of decoherence.
In this article, self-organizing-map-based video object segmentation is proposed, assuming that either Y-quantification or HSV-quantification can be systematically selected. Given a video sequence, the value of the probability density function for each component value is calculated according to a kernel estimation at the first frame. Some areas randomly chosen from the background are then examined, using each component value, to judge whether or not they include the target object. The quantification is determined so that the frequency of occurrence of false extractions can be reduced. The data presented to the maps are generated based on the selected quantification. Experimental results show that the proposed method recognizes the target object well.
This work is focused on effect of various cooling strategies on surface roughness and tool wear during computer aided milling of soft workpiece materials. These milling operations were selected as dry milling, cool air cooling milling and fluid cooling milling. A cool air cooling system was designed and produced to cool end milling tools. Cool air was produced by a vortex tube. Annealed AISI 1050 was used as the workpiece material and cutting tool material was selected as HSS-Co8 DIN 844/BN. Optimal cutting parameters were selected according to workpiece hardness from reference catalog and kept for all tests. Tool wear and surface quality were measured for three different cooling types changing from ten minute machining time to thirty minute machining time. As a result, the surface roughne...
This experiment is carried out in the series of the investigation on the damage mechanism of carbon steel. In this paper, the damage situation is considered by structure observations. The test were carried out in 600degC-1200degC temperature range, in blowing an argon gas. The reagents are Na{sub 2}O, Na{sub 2}O{sub 2} and NaOH. From structure observations, the holes are observed on the surface of iron-base material in some test conditions. This result is indicated that the selective reaction occurs. The selective reaction is more obvious as the time exposed to the high temperature is longer. It is considered that the selective reaction occurs after the chemical reaction between iron-base material and sodium compound. The areas, in which Mn-concentration is higher, are observed in products on the surface of specimen. (author)
Supercritical CO2 is used as a new solvent for immersion deposition, a galvanic displacement process traditionally carried out in aqueous HF solutions containing metal ions, to selectively develop metal films on featured or non-featured silicon substrates. Components of supercritical fluid immersion deposition (SFID) solutions for fabricating Cu and Pd films on silicon substrates are described along with the corresponding experimental setup and procedure. Only silicon substrates exposed and reactive to SFID solutions can be coated. The highly pressurized and gas-like supercritical CO2, combined with the galvanic displacement property of immersion deposition, enables the SFID technique to selectively deposit metal films in small features. SFID may also provide a new method to fabricate palladium silicide in small features or to metallize porous silicon.
Eight selected sulfonamide drugs were investigated as inhibitors of heat shock protein 90 (Hsp90). The investigation included simulated docking experiments to fit the selected compounds within the binding pocket of Hsp90. The selected molecules were found to readily fit within the ATP-binding pocket of Hsp90 in low-energy poses. The sulfonamides torsemide, sulfathiazole, and sulfadiazine were found to inhibit the ATPase activity of Hsp90 with IC50 values of 1.0, 2.6, and 1.5 mM, respectively. Our results suggest that these well-established sulfonamides can be good leads for subsequent optimization into potent Hsp90 inhibitors.
Target materials for inertial fusion energy (IFE) power plant designs might be selected for a wide variety of reasons including wall absorption of driver energy, material opacity, cost and ease of fabrication. While each of these issues are of great importance, target materials should also be selected based upon their safety and environmental (S and E) characteristics. The present work focuses on the recycling, waste management and accident dose characteristics of potential target materials. If target materials are recycled so that the quantity is small, isotopic separation may be economically viable. Therefore, calculations have been completed for all stable isotopes for all elements from lithium to polonium. The results of these calculations are used to identify specific isotopes and elements that are most likely to be offensive as well as those most likely to be acceptable in terms of their S and E characteristics.
The ATLAS High Level Trigger (HLT) is a distributed real-time software system that performs the final online selection of events produced during proton-proton collisions at the Large Hadron Collider (LHC). It is designed as a two-stage trigger and event filter running on a farm of commodity PC hardware. Currently the system consists of about 850 processing nodes and will be extended incrementally following the expected increase in luminosity of the LHC to about 2000 nodes. The event selection within the HLT applications is carried out by specialized reconstruction algorithms. The selection can be controlled via properties that are stored in a central database and are retrieved at the startup of the HLT processes, which then usually run continuously for many hours. To be able to respond to changes in the LHC beam conditions, it is essential that the algorithms can be re-configured without disrupting data taking while ...
The performance of Ag-promoted Pd/Al2O3 catalysts, which were prepared by the selective deposition of Ag onto Pd using a surface redox (SR) method, during acetylene hydrogenation was compared with that of catalysts prepared by impregnation. The Pd surface was more effectively modified with Ag added by SR, even when small amounts of Ag were added. The catalyst prepared by SR showed a higher ethylene selectivity than the one prepared by impregnation, because SR allowed both the preferential deposition of Ag on the low-coordination sites of Pd and a greater electronic modification of Pd by Ag.
Background: Measurements from pressure biofeedback units (PBUs) can be used to evaluate the activity of the transversus abdominis (TrA) muscle indirectly. These measurements can classify patients or monitor the progress of treatment programmes for people with low back pain. Objective: To systematically review studies on the measurement properties of PBUs for the assessment of TrA activity. Data sources: Eligible studies were identified through searches of PUBMED, CINAHL and BIREME (1990 to 2009). In addition, hand searches of journals and citation tracking were performed. Study selection: Full-text studies involving any type of clinimetric tests of PBU measurement for the assessment of TrA activity were selected. Data extraction: Two independent reviewers selected the studies, extracted th...
The Seabed Disposal Project (SDP) was evaluating the technical feasibility of high-level nuclear waste disposal in deep ocean sediments. Working standards were needed for risk assessments, evaluation of alternative designs, sensitivity studies, and conceptual design guidelines. This report completes a three part program to develop radiological standards for the feasibility phase of the SDP. The characteristics of subseabed disposal and how they affect the selection of standards are discussed. General radiological protection standards are reviewed, along with some new methods, and a systematic approach to developing standards is presented. The selected interim radiological standards for the SDP and the reasons for their selection are given. These standards have no legal or regulatory status and will be replaced or modified by regulatory agencies if subseabed disposal is implemented. 56 refs., 29 figs., 15 tabs.
Indoor and soil gas Radon (222Rn) concentration measurements were accomplished in two stages in Sivas, a central eastern city in Turkey. In the first stage, CR-39 passive nuclear track detectors supplied by the Turkish Atomic Energy Authority (TAEA) were placed in the selected houses throughout Sivas centrum in two seasons; summer and winter. Before the setup of detectors, a detailed questionnaire form was distributed to the inhabitants of selected houses to investigate construction parameters and properties of the houses, and living conditions of inhabitants. Detectors were collected back two months later and analysed at TAEA laboratories to obtain indoor 222Rn gas concentration values. In the second stage, soil gas 222Rn measurements were performed using an alphameter near the selected h...
Tissue hypoxia is a feature of cancer, heart disease and stroke, and imaging it may become clinically important. Copper-ATSM (ATSMH2 = 2,3-butanedione bis(N-methyl)thiosemicarb-azone), labelled with 60Cu, 62Cu or 64Cu, is selectively taken up in hypoxic cells in vitro and in vivo by a bioreductive mechanism, and is a prototype hypoxia imaging agent amenable to improvement. In vitro studies with several differently alkylated analogues of CuATSM show that hypoxia selectivity is a general property of complexes with two alkyl groups at the diketone backbone, offering a range of pharmacokinetic properties while retaining hypoxia selectivity. This pharmacokinetic control affords a route to development of second-generation hypoxia imaging agents with optimized properties for different clinical ap...
Thermophotovoltaic (TPV) converters were developed and tested at the heat source operating temperature of 1,700 K. Rare-earth-doped yttrium aluminum garnet (YAG) and lutetium yttrium aluminum garnet (Lu, YAG) selective emitters, as well as a blackbody emitter, were coupled to InGaAs/InP photovoltaic (PV) cells and bandpass/infrared (IR) reflector filters. YAG-based selective emitters were adopted with Ho, Tm, and Er. PV cells had bandgaps of 0.51, 0.57, and 0.69 eV. Converter energy conversion efficiencies approaching 30%, as well as electrical output power densities near 2 W/cm{sup 2} were demonstrated. The overall performance of the filtered blackbody-based converter was found to be superior to the selective emitter YAG-based converters. The details of the measurements performed on the above converters and their individual components are presented.
Depletion studies are used to infer the presence of mantles and to constrain grain evolutionary models in the diffuse interstellar medium. The presence of these mantles appears to be important in the evolution of the grains inside diffuse as well as dense clouds. In dense clouds where the element-to-element abundances sometimes differ from those found in diffuse clouds, empirical relationships are starting to emerge between gas abundances and various types of peculiar selective extinction. These peculiar extinction curves may be the results of nonvolatile mantle formation on grain cores or may reflect chemical differences due to variations in the intrinsic metalicity from one cloud to another. A simple model of the time evolution of a parcel of gas and dust as observed by the depletion of two elements is presented. Different studies of grain evolution and selective extinction are discussed and compared.
Using an efficient criterion in selection of fuzzy conditional attributes (i.e. expanded attributes) is important for generation of fuzzy decision trees. Given a fuzzy information system (FIS), fuzzy conditional attributes play a crucial role in fuzzy decision making. Besides, different fuzzy conditional attributes have different influences on decision making, and some of them may be more important than the others. Two well-known criteria employed to select expanded attributes are fuzzy classification entropy and classification ambiguity, both of which essentially use the ratio of uncertainty to measure the significance of fuzzy conditional attributes. Based on fuzzy-rough technique, this paper proposes a new criterion, in which expanded attributes are selected by using significance of fuz...
In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.
Rationale Smokers report enhanced concentration after cigarette smoking and difficulty concentrating when abstinent from smoking. These perceived effects may contribute to smoking cessation failures, and if so, clarification of their cognitive bases could inform treatment strategies. Selective attention may be important in this regard, but earlier literature presents inconsistent findings on how smoking abstinence and resumption of smoking influence this cognitive function. Objectives We aimed to compare smokers and nonsmokers on selective attention, and in smokers, to test the effects of overnight abstinence from smoking and of acute smoking on selective attention. Materials and methods Smokers and nonsmokers (n?=?43) performed a Stroop test (two test days, two test blocks per day). Smoke...
An array of sonic transducers, useful for medical ultrasonic imaging, has individual sections thereof separately coupled for forming separate beams of sonic energy which converge, respectively, to separate foci along a common axis of the beams. The ratio of the diameter of the radiating aperture of the array relative to a wavelength of the sonic energy is chosen to provide a moderate degree of focusing so that the depth of field at one focus blends with the depth of field of the next focus. Thereby, there is formed a continuous region of substantially uniform intensity of sonic radiation along the common beam axis. Circuitry is provided for selecting one or more specific foci dependent on the bounds of a selected region to be insonified. Upon reception of sonic energy, circuitry is provided for selecting one or more specific foci as a function of the time of travel of an echo from a subject being observed to approximate a ...
Thermophotovoltaic energy conversion achieves direct conversion of thermal energy to electricity without the need for complex dynamic machinery operating in one of several possible thermodynamic cycles. This paper presents an analysis of a hybrid solar thermophotovoltaic (STPV) energy conversion system in which a receiver/photovoltaic (PV) array subsystem is powered by either a solar concentrator or a fossil fuel combustion source. The overall TPV system efficiency is calculated using an appropriate selective emitter and a spectrally tuned solar cell designed to achieve maximum conversion efficiency in the narrow band emitted by the selective emitter. Two limiting cases are examined to place upper and lower bounds on system performance. The estimates of system performance are based on actual experimental data from PV cells and selective emitters.
The Decree specifies basic quality assurance requirements applicable to machines, their parts and materials, civil engineering structures, means for automated control of technological processes including hardware and software, and electricity supply systems related to nuclear safety of nuclear facilities, and stipulates binding procedures for the implementation of technical and organizational provisions associated with the quality of selected equipment to ensure nuclear safety of nuclear facilities. Safety classes are defined for selected equipment. Requirements laid on safety assurance documentation are specified, and requirements placed on safety assurance programmes, their preparation, finalization and approval are defined. Quality assurance requirements are also specified with respect to the designing, manufacture, construction, operation, repair, modification and decommissioning of nuclear facilities. The Decree entered into force on 1 ...
Poplar breeding in Europe is in a more advanced state than breeding programmes of other species. In Europe, poplars are part of the scenery and are integrated in the economy. Traditionally poplar stands are established in lowland areas. But an increasing interest in their use moved them to upland sites. Poplar uses are multiple: lumber, industrial wood, wind-breaks and landscape plantations, etc. Selection characteristics are classified in different groups: vegetative propagation ability, vigor, adaptation to sites and climate, resistance to diseases and insect pests, wood quality, and coppicing ability. Strategies have improved with time. The most efficient strategies for the long term involve constitution of base populations, selection of parents for intra- and interspecific hybridizations, selection within the progenies, and vegetative propagation. Short term strategies are also applied simultaneously. Advanced breeding ...
We have developed efficient spectrally selective infrared (IR) emitters that can be utilized for thermophotovoltaic (TPV) power generation by using stainless steel (SUS304) substrates coated with b- FeSi2 thin films. To develop spectrally selective emitters, we theoretically propose antireflection (AR) coatings consisting of a single layer of a dielectric material having a high refractive index (~5) and are appropriate for use with metals such as stainless steels in the IR region. This type of AR coating is fabricated by sputtering a b- FeSi2 thin film on a polished SUS304 substrate. The reflectance in the IR region is successfully reduced to less than 10%. In addition, the AR properties are stable even at 700 K in air. Therefore, metals with AR coatings of b- FeSi2 can be applied to IR em...
Ethnobotanical and chemotaxonomical studies for antiparasitic activity of Colombian Annonaceae were carried out. In vitro antiprotozoal activity of 36 extracts obtained from six different species was determined against promastigotes of three Leishmania species, epimastigotes of Trypanosoma cruzi and both chloroquine sensitive (F32) and resistant (W2) Plasmodium falciparum. Cytotoxic activity was evaluated in U-937 cells. Active extracts were selected according their selectivity index (SI). Extracts from Annona muricata, Rollinia exsucca, Rollinia pittieri and Xylopia aromatica were active against Leishmania spp. and Trypanosoma cruzi showing IC50 values lower than 25mg/ml. Hexane extract from Rollinia pittieri leaves was the most selective against Trypanosoma cruzi and Leishmania spp. (IS=...
Incorporating Environmentally Conscious Materials Selection in CAD System Narito Shibaike, Matsushita Electric, Japan ...Ikeda, Matsushita Erectric H.Ishida, INAX Y.Ishikawa, Japan Techno-Economics ...Tsuchiya*, Matsushita Electric Com- ponents Y.Tsuchiya*, Society of Japanese Value
A brief overview if provided of selected reports presented at the International Symposium on Molecular Mechanisms of Radiation- and Chemical Carcinogen-Induced Cell Transformation held at Mackinac Island, Michigan on September 19-23, 1993.
Pituitary Fshb concentrations increase markedly and selectively beginning on Postnatal Day 20 in the male rat. To evaluate the factors potentially responsible for this rise...Full Text Available
Skip to Content Cancer Control and Population Sciences Home Applied Research Home Risk Factor Monitoring and Methods Home Diet Usual Dietary Intakes: Background The NCI Method Details of the NCI Method Food Intakes, US Population, 2001-04 Selected Intakes
Skip to Content Cancer Control and Population Sciences Home Applied Research Home Risk Factor Monitoring and Methods Home Diet Usual Dietary Intakes: Background The NCI Method Details of the NCI Method Food Intakes, US Population, 2001-04 Selected Intakes
BackgroundMicroarray studies can supplement QTL studies by suggesting potential candidate genes in the QTL regions, which by themselves are too large to provide a limited selection...Full Text Available
BackgroundThe use of measurement tools is an essential part of good evidence-based practice; however, physiotherapists (PTs) are not always confident when selecting, administering,...Full Text Available
BackgroundSelection programs for growth and stress traits in cultured fish are fundamental to the improvement of aquaculture production. The gilthead sea bream (Sparus aurata)...Full Text Available
Select members of the Reoviridae are the only nonenveloped viruses known to induce syncytium formation. The fusogenic orthoreoviruses accomplish cell-cell fusion through a distinct...Full Text Available
Systems biology is a rapidly expanding field that integrates diverse areas of science such as physics, engineering, computer science, mathematics, and biology toward the goal of elucidating the underlying...Full Text Available
Mitochondria and peroxisomes execute some analogous, nonredundant functions including fatty acid oxidation and detoxification of reactive oxygen species, and, in response to select metabolic cues, undergo...Full Text Available
Highly polymorphic genes with central roles in lymphocyte mediated immune surveillance are grouped together in the major histocompatibility complex (MHC) in higher vertebrates. Generally, across vertebrate...Full Text Available
Accelerated aging tests on tin-oxide-coated anodized aluminium selective absorber surfaces have been performed. It is shown that the tin oxide layer provides excellent protection for the anodized surface. The thermal stability of the double layer is equal to, or better than, the stability of the bare anodized surface. Both surfaces degrade very slowly at 450deg C. The anodic layer is porous and therefore not very scratch resistant and it degrades when exposed to humidity, both acidic and alcaline. It is shown that the tin oxide film, which is hard and chemically very stable, almost completely protects the anodized surface from chemical degradation. The mechanical wear resistance is also considerably improved. The optical selectivity does not quite match that of the the anodized surface, but the remarkable stability together with the solar parameters of {alpha}=0.91 and hemispherical emittance {epsilon}= 0.16 (normal emittance {epsilon}{sub ...
SummarySurvival requires the selection of appropriate behavioural responses in the face of danger. With respect to the threat of predation, both the decision to escape and the underlying...Full Text Available
1. The stereospecificity of the enantiomers of LY253352, a potent and selective alpha 1-adrenoceptor antagonist, were studied in the human prostate and canine brain using radioligand receptor binding...Full Text Available
Hypoxia inducible factor-1 (HIF-1) promotes tumor cell adaptation to microenvironmental stress. HIF-1 is up-regulated in irradiated tumors and serves as a promising target for radiosensitization....Full Text Available
Lists of reportable conditions and case definitions are important tools for epidemiologic surveillance. As part of an initiative to encourage occupational disease surveillance systems linked to intervention...Full Text Available
Ecological speciation is the process by which barriers to gene flow between populations evolve due to adaptive divergence via natural selection. A relatively unexplored area in ecological speciation...Full Text Available
The study involved 110 randomly selected dairy farms located in the Ontario, Canada counties of Bruce, Grey, Huron, Oxford, Perth, Waterloo and Wellington. Herds were classified as "intensive" and "extensive"....Full Text Available
There is a quest for the development of a new generation of vaccines consisting of well-defined subunit antigens. For a number of practical reasons it is attractive to develop vaccines on the basis...Full Text Available
BackgroundFood supply from the ocean is constrained by the shortage of domesticated and selected fish. Development of genomic models of economically important fishes should assist...Full Text Available
This investigation will explore the effect that current timber extraction techniques have on plethadontid salamander populations in ... group selection, and two-age harvest. Broad scale timber extraction can d...
The C-C chemokine receptor 5, 32 base-pair deletion (CCR5-Δ32) allele confers strong resistance to infection by the AIDS virus HIV. Previous studies have suggested...Full Text Available
Allen's Rule documents a century-old biological observation that strong positive correlations exist among latitude, ambient temperature, and limb length in mammals. Although genetic selection for thermoregulatory...Full Text Available
Peptide toxins with high affinity, divergent pharmacological functions, and isoform-specific selectivity are powerful tools for investigating the structure-function relationships of voltage-gated...Full Text Available
OPERATE AT SOUTH POLE WINTER AMBIENTS, GIVEN THE PROJECT'S BUDGET AND TIME LINES . ... 17 MAXIMUM ELECTRICAL LENGHT CONSTRAINED BY Ku-BAND AT 50 FT. ... A MAXIMUM LENGTH OF 50 FEET HAS BEEN SPECIFIED BY THE SYSTEM LINK CALCULATIONS TO ...
A system for partial mechanisation of the support work with roadway driving machines consisting of a crawler undercarriage carrying a selective cutter with a cutting jib on a rotary tower is claimed. The system comprises a support manipulator movable in longitudinal direction over the rotary tower and cutting jib and a preassembly table with a number of brackets to take up and preassemble a support structure consisting of profile segments, preferably an arc-shaped support with a cap made up for several parts. The system is characterized in that the preassembly table is mounted on one side of the selective cutter and has one straight vertical guide bar each for at least two cap brackets which can be continuously adjusted in height, and in that the manipulator mounted on the selective cutter has a horizontally suivelling head which may grip under the cap of the preassembled structure on the preassembly table.
BackgroundVisual neurons respond essentially to luminance variations occurring within their receptive fields. In primary visual cortex, each neuron is a filter for stimulus features...Full Text Available
Several dissimilatory, sulfate-reducing bacteria were isolated from the rumen fluid of sheep fed purified diets containing sulfate. One isolate, strain D, was selected for characterization. This organism...Full Text Available
The objective of this study is to develop a method to aid in the selection of an overburden handling system in surface coal mining. The selection procedure consists of three major parts. The first part is aimed at rating the equipment's potential to perform the environmental protection related activities and then integrating this rating into the system selection process. The second part is an engineering analysis of the design of pit layouts and the operation of alternative overburden handling systems. The third part consists of a cost and sensitivity analysis of alternative systems on different mining situations. Specifically, the work includes: (1) a Delphi study to determine the magnitude of the environmental impacts and to quantify the relationship between mining practices and environmental remedies, (2) a scoring model to set up an index of the relative capability of equipment to do the environmental ...
Reported in this paper are the theoretical and experimental studies, with regard to the effects of radiation between walls, conducted for the improvement of heat transfer characteristics of the circular duct in high temperature heat exchangers that operate through the medium of non-radiating gases at around 1,000"0C. To study the fundamental performance of the heat transfer augmentation, the experiment was carried out using a double tube at temperatures up to 900"0C. The outer tube in a double tube was selectively heated so as to give a uniform heat flux selected of 6.5 x 10"3 and 4.6 x 10"4 kcal/m"2.h, while the inner tube was used as a radiating surface to impart the radiation heat transmitted from the outer tube. Selectively preheated air was caused to flow in an annular passage at an inlet temperature selected within 100"0C to 400"0C and with the Reynolds number of 2.9 x 10"3 to 3.5 x 10"4. The heat ...
A method is reported which permits selective suppression of absorption of radioactive strontium from ingested food material, permitting the calcium to be available to the body. Studies were carried...Full Text Available
Reactive blue 2 (RB-2) had been characterized as a relatively potent ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) inhibitor with some selectivity for NTPDase3. In search for the pharmacophore...Full Text Available
The view of species as entities subjected to natural selection and amenable to change put forth by Charles Darwin and Alfred Wallace laid the conceptual foundation for understanding speciation. Initially...Full Text Available
The effects of selected ligands on the structure of the truncated heavy-chain chemomechanical motor domains of Drosophila ncd and human kinesin were compared using the technique of transient electric...Full Text Available
Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium...Full Text Available
Sexually-selected communication signals can be used by competing males to settle contests without incurring the costs of fighting. Steroid regulation of these signals can render them as reliable...Full Text Available
BackgroundCelecoxib, a selective cyclo-oxygenase-2 inhibitor has been recommended orally for the treatment of arthritis and osteoarthritis. Long term oral administration of celecoxib...Full Text Available
This guide has been written to introduce growers of Short Rotation Coppice (SRC) to the principles and need for cold storage of planting material. The main types of cold store are described. It also provides assistance in the selection of suitable stores and how these are located nationally. (author)
This report of an interview with T. Watamori, Chairman of the Board of Directors of the New Energy Development Organization (NEDO), Japan outlines the general activities of NEDO, and then gives emphasis to the prospects of the liquefaction of brown coal from Australia. (In Japanese)
The oxidative dehydrogenation (OXDH) of n-butane, 1-butene, and trans-2-butene on different vanadia catalysts has been compared. MgO, alumina, and Mg-Al mixed oxides with Mg/(Al + Mg) ratios of 0.25 and 0.75 were used as supports. The catalytic data indicate that the higher the acid character of catalysts the lower is both the selectivity to C{sub 4}-olefins from n-butane and the selectivity to butadiene from both 1-butene or trans-2-butene. Thus, OXDH reactions are mainly observed from n-butane and butenes on basic catalysts. The different catalytic performance of both types of catalysts is a consequence of the isomerization of olefins on acid sites, which appears to be a competitive reaction with the selective way, i.e., the oxydehydrogenation process by a redox mechanism. Infrared spectroscopy data of 1-butene adsorbed on supported vanadium oxide catalysts suggest the presence of different adsorbed species. O-containing ...
The goal of ultrasonic molecular imaging is the detection of targeted contrast agents bound to receptors on endothelial cells. We propose imaging methods that can distinguish adherent microbubbles...Full Text Available
Background:Endothelin-1 may be involved in the development of diabetic microangiopathy. We studied the effect of endothelin-1 blockade on myocardial microcirculation during coronary...Full Text Available
We describe the interactions of two benzimidazole derivatives, astemizole (AST) and lansoprazole (LNS), with anomalous aggregates of tau protein (neurofibrillary tangles). Interestingly, these...Full Text Available
In all mammals, tissue inflammation leads to pain and behavioral sensitization to thermal and mechanical stimuli called hyperalgesia. We studied pain mechanisms in the African naked mole-rat, an unusual...Full Text Available
The thalamic reticular nucleus (TRN) consists of GABA-containing neurons that form reciprocal synaptic connections with thalamic relay nuclei. Excitatory synaptic innervation of TRN neurons arises from...Full Text Available
A general method is described to sequester peptides containing azides from complex peptide mixtures, aimed at facilitating mass spectrometric analysis to study different aspects of proteome...Full Text Available
By pretreating simian virus 40-infected BSC-1 cells with glucosamine, [3H]uridine labeling of both cellular and viral RNA can be halted instantaneously by addition of cold uridine. We have...Full Text Available
A report is made of operant conditoning procedures used in the determination of auditory, olfactory and visual acuity measures in the German Shepherd. An account is given of a procedure for semi-automatic training of dogs to search for, detect, and object...
A DNA sequence encoding the A chain of ricin toxin (RTA) from the castor bean plant, Ricinus communis, was placed under GAL1 promoter control and transformed into Saccharomyces cerevisiae. Induction...Full Text Available
A protein evolution strategy is described by which double-stranded DNA fragments encoding defined E. coli protein secondary structural elements (α-helices, β-strands...Full Text Available
I present results for the mass spectrum of excited baryons and pentaquarks using overlap fermions and Bayesian curve-fitting method; and magnetic moments and polarizabilities for a variety of hadrons in the background field method.
I present results for the mass spectrum of excited baryons and pentaquarks using overlap fermions and Bayesian curve-fitting method; and magnetic moments and polarizabilities for a variety of hadrons in the background field method.
of Colorado at Boulder Search This Site Natural Hazards Observer Disaster Research CU Web Site CU People go Search This Site Natural Hazards Observer Disaster Research CU Web...
The specific white matter location of all the spinal pathways conveying penile input to the rostral medulla is not known. Our previous studies using rats demonstrated the loss of low but not high threshold...Full Text Available
This glossary contains over 750 terms encountered in international maritime law texts. It includes terms of the art, fairly common abbreviations, geographic names, and prepositional phrases routinely encountered in international treaties, conventions, and...
Especially in bulk goods conveying, roller bearings must be selected with a vie to the intended application. Bulk goods conveying machinery consists of many different components that must interact as perfectly as possible.
A positive, genetic selection against the activity of the nitrogen regulatory (NTR) system was used to isolate insertion mutations affecting nitrogen regulation in Klebsiella aerogenes. Two classes...Full Text Available
Selection of the denitrifying community by plant roots (i.e., increase in the denitrifier/total heterotroph ratio in the rhizosphere) has been reported by several authors. However, very few studies...Full Text Available
CSIRO is Australia's one and only federal government research organization. After a description of Australian coal resources and coal-related research, accounts are given of the selection of research topics at CSIRO and of the coal utilization and coal liquefaction research which is being undertaken.
This study presents a rapid and selective method for the recovery of lanthanides and yttrium, existing in economically interesting concentrations, from red mud, the byproduct of the alumina production. The leaching process is based on the extraction of these elements with diluted nitric acid from red mud under moderate conditions and without using any preliminary treatment. Several parameters such as leaching agents, contact time, temperature, pressure and solid to liquid ratio were investigated in order to achieve an optimum recovery. The process followed here was selected taking into account its efficiency for the selective recovery of yttrium and lanthanides, but also its suitability for the subsequent liquid-liquid extraction of the leaching solution for the separation of the individual lanthanides. The achieved recovery percentages were for Y about 90%, for the investigated heavy lanthanides (Dy, Er, Yb) up to 70%, for ...
This study presents a rapid and selective method for the recovery of lanthanides and yttrium, existing in economically interesting concentrations, from red mud, the byproduct of the alumina production. The leaching process is based on the extraction of these elements with diluted nitric acid from red mud under moderate conditions and without using any preliminary treatment. Several parameters such as leaching agents, contact time, temperature, pressure and solid to liquid ratio were investigated in order to achieve an optimum recovery. The process followed here was selected taking into account its efficiency for the selective recovery of yttrium and lanthanides, but also its suitability for the subsequent liquid-liquid extraction of the leaching solution for the separation of the individual lanthanides. The achieved recovery percentages were for Y about 90%, for the investigated heavy lanthanides (Dy, Er, Yb) up to 70%, for ...
In general, rapid morphological change in mammals has been infrequently documented. Examples that do exist are almost exclusively of rodents on islands. Such changes are usually attributed to selective...Full Text Available
In this study we compared the molecular signalling elicited by rexinoids, selective retinoid X receptor (RXR)-activators, in several organs (i.e. liver, kidney,...Full Text Available
A structurally conserved element, the trigger loop, has been suggested to play a key role in substrate selection and catalysis of RNA polymerase II (pol II) transcription elongation. Recently resolved...Full Text Available
BackgroundLiquid chromatography-mass spectrometry (LC-MS) is one of the major techniques for the quantification of metabolites in complex biological samples. Peak modeling is one...Full Text Available
The pathogenesis of Pseudomonas aeruginosa disseminated infections depends on bacterial interaction with blood vessels. We have hypothesized that in order to traverse the endothelial barrier, bacteria...Full Text Available
A Monascus pilosus strain was selected for production of intracellular α-galactosidase. Optimum conditions for mycelial growth and enzyme induction were determined. Galactose...Full Text Available
BackgroundConducted as part of the Urologic Diseases in America project whose aim was to quantify the burden of urologic diseases on the American public, this study focuses on Veterans...Full Text Available
During the 1920s and 1930s, a number of physicians created model premature infant stations in select hospitals, arguing that medicine could successfully treat premature infants, most of whom could be...Full Text Available
IntroductionPatients undergoing selective minor emergency and elective procedures are followed up by a nurse-led structured telephone review six weeks post-operatively in our hospital....Full Text Available
A polyolefin composition is described comprising: 100 parts by weight of polyolefin, not less than 0.5 part by weight of a polyamide selected from the group consisting of nylon 6 and nylon 66, and from 3 to 30 percent by weight of a novolak based on the weight of the polyamide.
Nowadays, percutaneous pulmonary valve implantation is a successful alternative to surgery for patients requiring treatment of pulmonary valve dysfunction. However, owing to the wide variety of implantation...Full Text Available
The ability to achieve tumor selective expression of therapeutic genes is an area that needs improvement for cancer gene therapy to be successful. One approach to address this is through the...Full Text Available
BackgroundTo evaluate the performance of three different advanced treatment techniques on a group of complex paediatric cancer cases.MethodsCT...Full Text Available
The nucleocapsid protein (NC) of retroviruses plays a major role in genomic RNA packaging, and some evidence has implicated the matrix protein (MA) of certain retroviruses in viral RNA binding. To further...Full Text Available
Women experience a decline in estrogen and androgen levels after natural or surgically induced menopause, effects that are associated with a loss of sexual desire and bone mineral density. Studies in...Full Text Available
Electrophoretic analysis of protein variation at the coagulation F13B locus has previously revealed three alleles, with alleles 1, 2, and 3 each being at high frequency in European,...Full Text Available
Mycophenolate mofetil (MMF) is an immunosuppressive drug that acts as a selective inhibitor of inosine monophosphate dehydrogenase (IMPDH). MMF has recently been shown to inhibit the enzymatic activity...Full Text Available
A plasmid carrying the bacteriophage lambda lysis genes under lac control was subjected to hydroxylamine mutagenesis, and mutations eliminating the host lethality of the S gene were selected. DNA sequence...Full Text Available
The HTLV-1 Tax protein both activates viral replication and is involved in HTLV-1-mediated transformation of T lymphocytes. The transforming properties of Tax include altering the expression of select...Full Text Available
Laparoscopic colon surgery for select cancers is slowly evolving as the standard of care but minimally invasive approaches for rectal cancer have been viewed with significant skepticism. This procedure...Full Text Available
1. In normal rats and rats with bladder hypertrophy secondary to outflow obstruction, undergoing continuous cytometry, we examined the responses to the selective alpha 1-adrenoceptor antagonist doxazosin...Full Text Available
Pd-Si metallic glasses have been utilized as catalysts in the Fischer-Tropsch reaction. The glasses are selective of ethane, whereas the in-situ crystallized glasses select a range of hydrocarbons characteristic of conventional Pd catalysts. This shift in selectivity has been observed in other hydrogenation reactions. Surface crystallization caused by the reaction conditions causes variable selectivity. Crystallization in reaction conditions has been monitored by DSC. During the course of the grant we developed the use of (+)- apopinene (6,6-dimethyl-1R,5R-bicyclo(3.1.1)hept-2-ene) as a molecular probe for determining the number and kinds of active sites on metallic glass catalysts. To accomplish this we conducted many experiments for comparison on other types of catalysts. These were foils, powders, and highly dispersed metals on several different supports. The glassy surfaces appear to be three ...
BackgroundCD26 (dipeptidyl peptidase IV, DPPIV) is a 110 kDa surface glycoprotein expressed in most normal tissues, and is a potential novel therapeutic target for selected cancers....Full Text Available
We have exploited ``progeny testing'' to map quantitative trait loci (QTL) underlying the genetic variation of milk production in a selected dairy cattle population. A total of 1,518 sires, with progeny...Full Text Available
Introduction: Selective dissemination of information (SDI) services regularly alert users to new information on their chosen topics. This type of service can increase a user's ability to...Full Text Available
This manual provides information to assist in selection and designing control measures for reducing pollutant discharges from combined sewer overflows (CSOs). he manual will be useful for municipal public works staff, design engineers, and regulatory agency staff tasked with the ...
BackgroundThe various tasks of visual systems, including course control, collision avoidance and the detection of small objects, require at the neuronal level the dendritic integration...Full Text Available
The report gives results of the measurement of dissolution rates of reagent CaCO3 and commercial limestones (9 types/19 grinds) at constant pH and solution composition by batch titration with HC1. Conditions were selected to simulate flue gas desulfurizat...
Oryza sativa or Asian cultivated rice is one of the major cereal grass species domesticated for human food use during the Neolithic. Domestication of this species from the wild grass...Full Text Available
To assess the practical significance of reported increases in the prevalence of vancomycin-susceptible strains of Neisseria gonorrhoeae on isolation of this organism, antibiotic-free chocolate agar...Full Text Available
BackgroundGenetic interactions within hybrids influence their overall fitness. Understanding the details of these interactions can improve our understanding of speciation. One experimental...Full Text Available
Although cross-resistance in houseflies to the organophosphates has eliminated numerous potentially useful compounds from field use, the ”subgroup” specificity of this phenomenon has...Full Text Available
A series of N-alkylamide epoxides have shown considerable selective activity against insects. The N-ethyl and 7,11-dichloro-N-ethyl derivatives showed particularly pronounced activity, and this paper...Full Text Available
Pancreatic islet transplantation into the liver provides a possibility to treat selected patients with brittle type 1 diabetes mellitus. However, massive early β-cell death increases the number...Full Text Available
One selection pressure shaping sequence evolution is the requirement that a protein fold with sufficient stability to perform its biological functions. We present...Full Text Available
The nicotinic acetylcholine receptor (AChR) controls signal transmission between cells in the nervous system. Abused drugs such as cocaine inhibit this receptor. Transient kinetic investigations indicate...Full Text Available
The human immunodeficiency virus type 1 (HIV-1) packages its genomic RNA as a dimer of homologous RNA molecules that has to be selected among a multitude of cellular and viral RNAs. Interestingly, spliced...Full Text Available
Sauropod dinosaurs, the dominant herbivores throughout the Jurassic, challenge general rules of large vertebrate herbivory. With body weights surpassing those of any other megaherbivore, they relied...Full Text Available
Objective:To assess the efficacy of facet joint infiltrations for pain relief in 44 selected patients with chronic nonradicular low back pain (LBP).Materials...Full Text Available
Recent technological developments have facilitated intensified searches for genetic markers under selection in nonmodel species. Here, we present an approach for the identification of candidate gene variation in nonmodel organisms. We report on the characterization of 82 single nucleotide polymorphisms (SNPs) and on the development of a specific genotyping assay for 30 SNPs in 18 candidate genes for growth and reproduction in Atlantic cod (Gadus morhua). These markers can be used for scanning natural populations for signatures of selection in both contemporary and archived historical samples, for example in retrospective studies assessing the effects of environmental changes, such as increasing temperatures, and selection imposed by high fishing pressure. Furthermore, these gene markers may be of interest to aquaculture, serving as a starting point for linking phenotypic traits important for productivity with genotypes and ...
The principle of need selecting the game of Chicken ... The Chicken (e.g.Rasmusen, 1994) tells the story of two car drivers ...6 Therefore the Chicken is also characterised as a dilemma of common aversion (Rapoport &
A new organic-inorganic hybrid membrane has been prepared with exceptional performance in dewatering applications. The only precursor used in the sol-gel synthesis of the selective layer was organically linked 1,2-bis(triethoxysilyl)ethane (BTESE). The microporous structure of this layer enables selective molecular sieving of small molecules from larger ones. In the dehydration of n-butanol with 5% of water, the membrane shows a high separation factor of over 4000 and ultra-fast water transport at a rate of more than 20 kg m{sup -2} h{sup -1} at 150C. This can be related to the high adsorption capacity of the material and the sub-micron thickness of the selective layer. The selectivity has now remained constant over almost one and a half years under continuous process testing conditions. Apart from the hydrothermal stability, the membrane exhibits a high tolerance for acid contamination. A slow ...
The selection due to the "healthy worker effect" was estimated from a random sample of the total Finnish population. The sample of 20 000 people was followed for changes in occupations from 1960 to...Full Text Available
Neurons in the hippocampal CA1 region are particularly sensitive to oxidative stress (OS), whereas those in CA3 are resistant. To uncover mechanisms for selective CA1 vulnerability to OS, we...Full Text Available
Tamoxifen (TAM) is a selective estrogen receptor modulator widely used in the prevention and treatment of breast cancer. A major mode of metabolism of the major active metabolites of TAM, 4-OH-TAM...Full Text Available
Bit Plane Complexity Segmentation (BPCS) digital picture steganography is a technique to hide data inside an image file. BPCS achieves high embedding rates with low distortion based on the theory that noise-like regions in an image's bit-planes can be replaced with noise-like secret data without significant loss in image quality. . In this framework we will propose a collaborate approach for select frame for Hiding Data within MPEG Video Using Bit Plane Complexity Segmentation. This approach will invent high secure data hidden using select frame form MPEG Video and furthermore we will assign the well-built of the approach; during this review the author will answer the question why they used select frame steganography. In additional to the security issues we will use the digital video as a cover to the data hidden. The reason behind opt the video cover in this approach is the huge amount of single frames image per sec which ...
A method for recycling laser flashlamp radiation in selected wavelength ranges to decrease thermal loading of the solid state laser matrix while substantially maintaining the pumping efficiency of the flashlamp.
The heterogeneity of metastatic breast cancer mandates the need to select therapies taking into account tumor and patient characteristics. Chemotherapy is indicated in the palliative setting especially...Full Text Available
The task of selecting reliable computer programs to simulate the performance of passive solar buildings has been assigned by the CEC to a specialized sub-group, the Modelling Sub-Group. This group has selected a detailed program for large computers, which has been commissioned and run by each participant. It has also given a reference for the analysis of a set of simple models, i.e. for mini/micro computers, pocket calculators and manual methods. These simulation techniques have been analyzed by answering an original questionnaire, making test runs of the models with building and climatic data, and comparing the results obtained with the large program. The best manual method has been included in the Passive Solar Handbook prepared by the Passive Solar Working Group. The MSG has also established a comparative table of all the selected simplified models, in order to make the designer able to do a first ...
The Feynmann and other fluctuation techniques have been shown to be useful for determining the multiplication of subcritical systems. The moments of the counting distribution from neutron detectors is analyzed to yield the multiplication value. We present the methodology and some selected applications and results and comparisons with Monte Carlo calculations.
Microarray data has a high dimension of variables but available datasets usually have only a small number of samples, thereby making the study of such datasets interesting and challenging. In the task...Full Text Available
BackgroundProfessionalism is a difficult construct to define in medical students but aspects of this concept may be important in predicting the risk of postgraduate misconduct. For...Full Text Available
This volume is a summary of the results of the final report of the Energy Engineering Analysis Program (EEAP) Study of 30 selected dining facilities at Fort Campbell, Kentucky.
...comply with funding body archiving policies, including the policies put in place by the National Institutes of Health, The Wellcome Trust and the Howard Hughes Medical Institute . Delayed Access Select journals provide content to some or all of a journalrsquo;s backfile. For example, articles in ...
Bitter orange (Citrus aurantium) extract is widely used in dietary supplements for weight management and sports performance. Its primary protoalkaloid is p-synephrine....Full Text Available
The proper selection of materials of construction is necessary to provide process equipment with optimum performance and corrosion resistance. If properly chosen, the selected material should deteriorate at a uniform, predictable rate, which will allow for maintenance or replacement at scheduled intervals. This concept of risk assessment for predictive maintenance is a minimum requirement for proper materials selection. Materials selection is based on prior service history, field corrosion tests, pilot-plant tests, and laboratory bench-top tests--in that relative order of usefulness. Corrosion test methods are usually divided into two groups: laboratory and field (plant-site) tests. The main difference between the two is that field test specimens are exposed to actual process conditions will all of the variables involved, while laboratory tests are a simulation of field conditions, even if actual ...
Drugs used for the inhibition of DNA viruses, such as iododeoxyuridine, adenine arabinoside, or trifluorothymidine, are not biochemically selective in their action and also interfere with normal cellular...Full Text Available
MWo = average molecular weight of fuel est. 105 g/mole for gasoline est. 165 g/mole for Jet fuel est. 230 g/mole for diesel fuel MWX = molecular weight of selected chemical...
This project will determine whether electrolytic dialysis has promise in the separation of charged particles in an aqueous solution. The ability to selectively move ions from one aqueous solution to another through a semipermeable membrane will be studied as a function of emf, amperage, and particle electrical charge. The ions selected for the study are Cl{sup -} and SO{sub 4}{sup 2-}. These ions are of particular interest because of their electrical conduction properties in aqueous solution resulting with their association with the corrosive action of metals. The studies will be performed with commercial membranes on solutions prepared in the laboratory from reagent salts. pH adjustments will be made with dilute reagent acid and base. Specific objectives of the project include testing a selected membrane currently available for electrolytic dialysis, membrane resistance to extreme pH conditions, the effectiveness of ...
Bacillus thuringiensis was isolated from 36 of 50 residue samples obtained from an animal feed mill (a stored-product environment). Of 710 selected colonies having Bacillus...Full Text Available
In recent years, the National Toxicology Program (NTP) has selected numerous glycol ethers for testing in routine laboratory mammals to ascertain the magnitude of their ability to injure the conceptus....Full Text Available
The development of structural barriers for nuclear waste packages involves selection of candidate materials, their screening by mechanical and corrosion testing, rigorous accelerated testing, and evaluation and comparison with other package elements. This document presents results from work conducted on titanium and ferrous alloys.
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin. However, the role of the AHR...Full Text Available
A second-generation solar disinfection (SODIS) system (pouch) was constructed from food-grade, commercially available packaging materials selected to fully transmit and amplify the antimicrobial properties...Full Text Available
BackgroundLung volume reduction surgery is effective at improving lung function, quality of life, and mortality in carefully selected individuals with advanced emphysema. Recently,...Full Text Available
Food-deprived pigeons were presented with a row of four response keys situated above a grain hopper aperture. At the start of a trial, three of four keys were randomly selected and illuminated white...Full Text Available
A pure culture of an Agrobacterium sp. (deposited as ATCC 55002) that mineralizes the ferric chelate of EDTA (ferric-EDTA) was isolated by selective enrichment from a treatment facility...Full Text Available
Work continued on the correlations of catalytic activity of metals and surface structure. Work is described in the following areas: CO oxidation on a Cu/Rh(100) Bimetallic catalysts; electronic properties of bimetallic surfaces; and reflection absorption spectroscopy of bimetallic surfaces. 5 figs. (CBS)
Hepatitis B surface antigen (HBsAg) bound to immunoglobulin M (IgM) was detected in sera of HBsAg carriers by a radioimmunoassay based on selective absorption of the immunoglobulin on a solid phase...Full Text Available
BackgroundPlastid genome content and protein sequence are highly conserved across land plants and their closest algal relatives. Parasitic plants, which obtain some or all of their...Full Text Available
Background & AimsData are conflicting on the benefit of selective serotonin reuptake inhibitors (SSRIs) for patients with irritable bowel syndrome (IBS);...Full Text Available
After emergence, adult flies and other insects select a suitable perch and expand their wings. Wing expansion is governed by the hormone bursicon and can be delayed under adverse environmental...Full Text Available
The isomerization of neopentane has been investigated over the 0.76 wt% Pd/SiO{sub 2} catalyst. It is found that after high temperature reduction (HTR, at 873 K) the selectivity for isomerization is much higher than that after low temperature reduction (LTR, at 573 K). A variety of experiments, including kinetic, chemisorption (O{sub 2}, H{sub 2}, and CO), temperature-programmed desorption of H{sub 2}, and X-ray diffraction, showed that this selectivity enhancement cannot be interpreted in terms of H{sub 2} retention by catalyst. Instead, the formation of Pd-Si compound(s) (most probably Pd{sub 3}Si) during HTR seems immediately responsible for the catalytic behavior of HTR Pd/SiO{sub 2} catalysts. A mechanism is proposed for the Pd-SiO{sub 2} interaction in which Pd atoms (or ions) are incorporated into the silica support (via oxygen vacancies) and a new phase of palladium silicide is formed. Regeneration by an oxygen treatment of the HTR ...
This book contains over 20 selections. Some of the titles are: Continuum damage mechanics studies on the dynamic fracture of concrete; Dynamic compressive strength of cementitious materials; Rate-sensitivity of mode I and mode II fracture concrete; and An impact damage model of concrete.
Cd36 is a small-molecular-weight integral membrane protein expressed in a diverse, but select, range of cell types. It has an equally diverse range of ligands and physiological functions, which has...Full Text Available
A process is claimed for selectively preparing alpha-olefins having from 2 to about 22 carbon atoms by contacting a gaseous mixture containing carbon monoxide and hydrogen with an iron titanate alkali metal hydroxide catalyst at reaction conditions correlated so as to favor the formation of a substantial proportion of such alpha-olefin product.
1. The effect of capsaicin pre-treatment on adrenal catecholamine (CA) secretion in response to stress is controversial. In earlier experiments performed under pentobarbitone anaesthesia, the release...Full Text Available
Enzyme kinetic studies from this laboratory (M. Dobersen and S. Greer, Biochemistry 17:920-928, 1978) suggested that deoxycytidine could antagonize the toxicity of 5-halogenated analogs of deoxycytidine...Full Text Available
This paper aims to highlight ways in which basic research findings in the field of childhood and adolescent depression can help to inform and refine preventive intervention efforts. We selectively review...Full Text Available
The diagnostic accuracy of computed tomography (CT) in several patterns of thoracic and abdominal fatty masses, has been examined. In selected cases our findings overlap the features of the recent literature. The possibility of surgical therapy in peculiar cases of adipose deposits, commonly esteemed benign, is considered.
Recently, CID755673 was reported to act as a highly selective inhibitor of protein kinase D (PKD). In the course of experiments using CID755673, we noticed that it exerted unexpected stimulatory...Full Text Available
Previous work has implicated prefrontal cortices in selecting among and retrieving conceptual information stored elsewhere. However, recent neurophysiological work in monkeys suggests that prefrontal...Full Text Available
Activities are reported in programs to locate, test, and select materials for borehole plugs near nuclear waste repositories. Background information concerning borehole plugging is presented and work to date is summarized. Borehole sealants considered are listed and recommended steps to plug boreholes are given. Planned research is summarized.
Two nitrate reductase (NR) mutants were selected for low nitrate reductase (LNR) activity by in vivo NR microassays of M2 seedlings derived from nitrosomethylurea-mutagenized...Full Text Available
Bacterial pathogens use virulence strategies to invade epithelial barriers, but active processes of epithelial cells may also contribute to the endocytosis of microbial particles. To focus on the latter,...Full Text Available
OBJECTIVE: To measure the prevalence of urethritis due to Neisseria gonorrhoeae and Chlamydial infection trachomatis in rural Tanzanian men DESIGN: About 500 men aged 15-54 years were selected from...Full Text Available
Data from an epidemiological study in Ontario, involving 304 dairy herds, were used to identify associations between selected production indices and lipoarabinomannan antigen serological test results...Full Text Available
In biotechnology, acrylamide is being used in DNA and RNA analysis using the polyacrylamide gel electrophoreses procedure. Polymerized acrylamide is degraded into acrylamide through time; it is converted into a hazardous contaminant that is carcinogenic and neurotoxic to animals and humans. Because ...
The carboxyl-terminal region of tubulin alpha and beta subunits plays a major role in regulating its assembly into microtubules and constitutes an essential domain for the selective interaction of microtubule-associated...Full Text Available
Transgenic mouse models have contributed considerably to our understanding of the cellular and molecular mechanisms by which androgens control spermatogenesis. Cell-selective ablation of the androgen...Full Text Available
Numerous xenobiotics, including therapeutics agents, are substrates for bioactivation to electrophilic reactive intermediates that may covalently modify biomolecules. Selective estrogen receptor...Full Text Available
Signatures of natural selection occur throughout the human genome and can be detected at the sequence level. We have re-sequenced ABCE1, a host candidate gene essential for...Full Text Available
BackgroundMalaria resistance by the sickle cell trait (genotype HbAS) has served as the prime example of genetic selection for over half a century. Nevertheless, the mechanism...Full Text Available
Monoclonal antibodies were produced against gamma-irradiated amastigotes of Leishmania major. Five antibodies (T16 through T20) were selected which reacted in enzyme-linked immunoassays with the intracellular...Full Text Available
This patent describes a delayed acrylamide containing polymer crosslinker having stability in an aqueous solution at high temperatures. It comprises: a combination of an aldehyde and a salicylic acid derivative selected from salicylamide and acetysalicylic acid.
This study describes instructions for after-hours care offered by family physicians' offices when patients telephone the practice. Randomly selected (n=1,680) Ontario family physicians and general practitioners...Full Text Available
Besides ethanol, acetic acid is produced in naturally fermenting sweet resources and is a significant environmental stress for fruit-breeding Drosophila populations and species. Although not related...Full Text Available
A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.
The rejection thresholds of the blowfly Phormia regina Meigen for a selected series of substituted aliphatic hydrocarbons have been determined and an analysis made of the effect on...Full Text Available
The problem of optimizing a horn radiator of electromagnetic waves for the reflection coefficient and the coefficient of transformation of the fundamental mode into higher order modes is solved. Optimization is performed by means of selecting a combined shape of the radiator generatrices.
Selective phosphodiesterase type 5 inhibitors (PDE5Is) have revolutionized the treatment of erectile dysfunction (ED) in men. As an on-demand treatment, PDE5Is have excellent efficacy and safety in...Full Text Available
A duplex TaqMan real-time RT-PCR assay was developed for the detection of California (CAL) serogroup viruses and Cache Valley virus (CVV), for use in human surveillance. The targets selected...Full Text Available
Little is known about the conservation of determinants for the identities of tRNAs between organisms. We showed previously that Escherichia coli tyrosine tRNA synthetase can charge the Saccharomyces...Full Text Available
Transthyretin aggregation-associated proteotoxicity appears to cause several human amyloid diseases. Rate-limiting tetramer dissociation and monomer misfolding of transthyretin (TTR) occur before...Full Text Available
Predation is generally thought to constrain sexual selection by female choice and limit the evolution of conspicuous sexual signals. Under high predation risk, females usually become less choosy, because...Full Text Available
Neocortical columns are functional and morphological units whose architecture may have been under selective evolutionary pressure in different mammalian lineages in response to encephalization and specializations...Full Text Available
BackgroundBacillus thuringiensis is a bacterium known for producing protein crystals with insecticidal properties. These toxins are widely sought after for controlling...Full Text Available
(General Stafford) was selected as chair for the Task Force based on his expertise .... a large foreign customer base that includes joint working agreements with Russia, the .... NASA Headquarters management advocates the Jorge Scientific ...
We propose a novel method for ultrasensitive isotope analysis that combines magnetic mass selection, resonant charge-exchange neutralization, and resonant laser ionizaion. Our method attains high isotopic abundance selectivity by means of continuous multistage separation of ions stored in a small ring. For the environmentally interesting case of /sup 90/Sr versus /sup 88/Sr we estimate that sensitivity better than 10/sup -15/ for a throughput of 10/sup 13/ atoms/sec and an efficiency (after the ion source) greater than 10% are readily achievable.
Apparatus and method for selective measurement of tritium oxide in an environment which may include other radioactive components and gamma radiation, the measurement including the selective separation of tritium oxide from a sample gas through a membrane into a counting gas, the generation of electrical pulses individually representative by rise times of tritium oxide and other radioactivity in the counting gas, separation of the pulses by rise times, and counting of those pulses representative of tritium oxide. The invention further includes the separate measurement of any tritium in the sample gas by oxidizing the tritium to tritium oxide and carrying out a second separation and analysis procedure as described above.
A new approach for the selection of best PSS locations in multimachine power systems is proposed in this paper. Study shows that the right-eigenvector measures the activity of state variables and the left-eigenvector measures the control effect of control signals. Based on the right and left eigenvector the concept of sensitivity of PSS effect (SPE) is presented and used to identify the best PSS locations. The proposed method is used to identify the best PSS location in a 13-machine system to increase the damping of an interarea mode. The time-domain simulation results confirm that the prediction of best PSS location by SPE method is correct and accurate.
This letter describes a new simple fabrication process, developed recently for blue response'' improvement in low-cost polycrystalline silicon solar cells. A selective emitter is created by heavily doping the emitter, followed by a wet etching-back of the cell area between the fingers. An improvement up to 17 mV in {ital V}{sub oc}, 1.5 mA/cm{sup 2} in {ital J}{sub sc}, and 1% (absolute value) in {eta} is obtained. Effective phosphorus gettering, self-alignment, and application in a low-cost full screenprinting technology are the main advantages of the proposed process.
Selective removal of hexavalent chromium ions from aqueous solutions using a chitosan/gold nanoparticles composite film was demonstrated. Localized surface plasmon resonance (LSPR) was used to measure the interface stability and detect the incorporation of chromium ions over time. The effects of pH, ethylenediaminetetraacetic acid (EDTA), and various foreign ions such as trivalent chromium, sodium, calcium, phosphate, sulfate and chloride on the adsorption of hexavalent chromium were investigated. PMID:19381379
The objective of the Korean Next Generation Reactor(KNGR) seismic design is to develop a standard design that can cover most of site characteristics in the world with the possible exception of areas of high seismicity. This seismic design was based on the current state-of-the-art as well as the current Nuclear Regulatory guidance. This paper provides a summary on the design parameters used in the KNGR seismic design. In addition, this paper discusses seismic design requirements, selection of generic soil sites, selection of design control motions, and soil-structure interaction(SSI) analyses for the KNGR Nuclear Island(NI) structures. (author). 16 refs., 8 figs.
Critical knowledge is proliferated among different knowledge owners of a corporate system through the individuals lying inside or outside the system. Extraction of such knowledge is a very crucial requirement for all organisations. This paper presents the role of critical knowledge in the proper functioning of a system by representing it in the form of eXtensible Markup Language to develop a corporate memory. In order to demonstrate the role of corporate memory in the organisation, a real-world problem of a global supply chain is considered. The problem utilises the concept of corporate memory for the selection of potential suppliers from a set of available suppliers, and further to select the best route from a set of available alternative routes. The objective deals with the minimisation ...
This paper presents a decision approach, and associated computer software tools, for prioritizing and selecting among technology development activities. The approach elicits and then summarizes technology development preferences from stakeholders, and then integrates preferences into a set of funding recommendations. By formalizing the technology review process, the decision approach builds consensus and clarifies the basis for final budget decisions. The software development was conducted jointly by Pacific Northwest Laboratory and Decisions Science Associates, Incorporated. The Underground Storage Tank Integrated Demonstration funded the task; however, the approach should also be valuable to the US Department of Energy Office of Technology Development, the Office of Waste Management, and the Office of Environmental Restoration.
The general types of pumped-storage plants and considerations for determining their need, use, and selection are presented. A brief discussion of TVA's experience on two pumped-storage schemes is included. Pumped-storage plants have become an integral part of many hydropower systems. Most of these systems use pumped-storage plants to meet power requirements during the peak load demands. In any application, large or small, the expected load demand and supply source must be identified to select the best scheme required for the particular system.
A process is claimed for selectively preparing a mixture of two-carbon atom oxygenated hydrocarbons, namely, acetic acid, ethanol and acetaldehyde, by continuously contacting a gaseous reaction mixture containing hydrogen and carbon monoxide with a solid catalyst comprising rhodium in combination with one or more alkali metals selected from the group consisting of lithium, potassium, cesium and rubidium at reaction conditions correlated so as to favor the formation of a substantial proportion of such two-carbon atom products.
The present invention provides a compound of the formula (Cat).sup.+.sub.z[M.sup.++(5-nitro-1H-tetrazolato-N2).sup.-.sub.x(H.sub.2- O).sub.y] where x is 3 or 4, y is 2 or 3, x+y is 6, z is 1 or 2, and M.sup.++ is selected from the group consisting of iron, cobalt, nickel, copper, zinc, chromium, and manganese, and (Cat).sup.+ is selected from the group consisting of ammonium, sodium, potassium, rubidium and cesium. A method of preparing the compound of that formula is also disclosed.
The present invention provides a compound of the formula (Cat).sup.+.sub.z[M.sup.++(5-nitro-1H-tetrazolato-N2).sup.-.sub.x(H.sub.2- O).sub.y] where x is 3 or 4, y is 2 or 3, x+y is 6, z is 1 or 2, and M.sup.++ is selected from the group consisting of iron, cobalt, nickel, copper, zinc, chromium, and manganese, and (Cat).sup.+ is selected from the group consisting of ammonium, sodium, potassium, rubidium and cesium. A method of preparing the compound of that formula is also disclosed.
This patent describes a process for preparing poly(aryl ether ketones) by nucleophilic displacement polymerization in the presence of at least one alkali metal base selected from potassium, rubidium or cesium, and fluoride ions, which comprises adding to the polymerization: (a) an effective amount of at least one metal salt selected from lithium, sodium, alkaline earth or lanthanide chloride, bromide, iodide, sulfate, alkyl or aryl carboxylate, cyanide, borate or phosphate to slow or stop advancement of molecular weight and (b) an end-capping agent.
Applying the thermochemical selectivity criterion of Hadnett et al. It is shown that the selectivity of the furan formation is not limited by a too low strength of the C-H bonds in furan when compared with the C-H bond dissociation energy in the educt molecule butadiene. In the oxidation of butadiene on a CsH{sub 2}PMo{sub 12}O{sub 40} catalyst a maximum yield of 22 mol% furan has been obtained. To improve this comparatively low furan yield oxidation activity of the catalyst must be lowered to prevent the consecutive reaction to maleic anhydride. (orig.)
The method of syndrome coding for data compression read out from multiwire proportional chambers that has been previously proposed is generalized in case of its application to registration of the coordinates of events detected. The questions of execution of arithmetic and algebraic operations on the Galois field elements and their hardware implementation are considered. The method of computation is presented of a specialized processor for parallel computing the coordinates of three sparks. The estimate of its speed is equal to 185 ns. Data compression, data selection and coordinate calculations are performed without use of memory elements and timing pulses.
Following revisions to the Tri-Party Agreement for Hanford Site cleanup, which specified vitrification for Complete melter feasibility and system operability immobilization of the low-level waste (LLW) tests, select reference melter(s), and establish reference derived from retrieval and pretreatment of the radioactive LLW glass formulation that meets complete systems defense wastes stored in 177 underground tanks, commercial requirements (June 1996). Available melter technologies were tested during 1994 to 1995 as part of a multiphase program to select reference Submit conceptual design and initiate definitive design technologies for the new LLW vitrification mission.
This chapter reports recent advances in the statistical learning literature that may be of interest for biometrics. In particular we discuss two different algorithmic settings, binary classification and multi-task learning, and analyze the two closely related problems of feature selection and feature learning. In the binary case the theoretical and algorithmic advances to feature selection are applied to solve face detection and face authentication problems. In the multi-task case we show how the data structure described by a group of features common to the various tasks can be effectively learned, and then we discuss how this approach could be used to address face recognition.
Catalytic testing of inorganic catalysts was continued with the highly active sulfate-modified zirconia catalyst prepared here. Using isobutanol as the only reactant over this catalyst, it was demonstrated that high conversion and selectivity to isobutene was achieved at 175[degrees]C. In addition, the high selectivity to isobutene, i.e. 79--86 mol%, was maintained at higher space velocities and higher temperatures. A high productivity of 11.35 mol isobutene was achieved at 225[degrees]C. Utilizing a methanol/isobutanol = 2/1 molar ratio reactant mixture over the ZrO[sub 2]/SO[sub 4][sup 2[minus
The use of a selective epitaxial growth technique for fabricating YBCO thin-film microstructures is described. No film post-deposition processing is required; hence damage to the structure is minimized. The technique is compatible with a passivation process to protect the structure without exposure to air. The microbridges, Josephson junctions and rf SQUIDs protected by an amorphous YBCO passivation have long lifetime even after severe accelerated aging tests. Rf SQUIDs fabricated by this technique show a significant reduction of low-frequency noise when operating in weak magnetic fields compared with SQUIDs fabricated by the conventional ion beam etching technique. (author)
Lithium was selectively extracted from near-neutral aqueous solutions of alkali metal salts. The mechanism by which this was achieved involves the formation of the trioctylphosphine oxide adduct of a lithium chelate of a fluorinated #beta#-diketone, which is then readily extractable into an organic diluent. High separation factors were obtained from sodium, potassium, rubidium, and cesium. The selectivity of the fluorinated #beta#-diketones for lithium over the alkaline earths was found to be poor. A suggested general flowsheet for the recovery of lithium from a salt brine concentrate is included. (author).
In order to understand the physical processes concerned with the selective heating by ion cyclotron resonance and with the subsequent collection of heated particles, experiments were carried out with the extraction of lithium samples, enriched with "6Li isotopes. Probe and integral extractors allow to collect enriched Li at the end of the selective heating region. Surface density distribution on the collector and local isotopic content of lithium are measured, as a function of the screen height and the retarding potential. Dependence of the collected amount of lithium and of its isotopic content on the value of the magnetic field is also measured. 4 figs., 2 tabs., 5 refs.
Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).
We have designed a new nucleobase, benzodeazaadenine (BDA) that has a stronger charge transport ability than guanine and is not destroyed during charge transport process. By incorporating this new nucleobase into DNA, we demonstrated a protocol for real DNA nano-wire that is far superior to natural DNA. We also demonstrated that the selectivity for the interaction of Mn(II) ion with guanine N7 in G runs is a HOMO-controlled process, and as a consequence, the selectivity for G-metal ion interactions obtained by 15N-NMR studies would directly reflect the HOMO distribution of G-containing sequences in B-DNA. PMID:12903077
The authors evaluated three of the top man-machine interface (MMI) software systems. The main categories upon which they based their evaluation on were the following: operator interface; network and data distribution; input/output (I/O) interface; application development; alarms; real-time and historical trending; support, documentation, and training; processing tools (batch, recipe, logic); reports; custom interfacing; start-up/recovery; external database; and multimedia. They also present their MMI requirements and guidelines for the selection and evaluation of these MMI systems.
This paper describes a novel Fourier transform infrared (FTIR) spectroscopic method that can be used to rapidly screen soil samples from potentially hazardous waste sites. Samples are heated in a thermal desorption unit and the resultant vapors are collected and analyzed in a long-path gas cell mounted in a FTIR. Laboratory analysis of a soil sample by FTIR takes approximately 10 minutes. This method has been developed to identify and quantify microgram concentrations of explosives in soil samples and is directly applicable to the detection of selected volatile organics, semivolatile organics, and pesticides.